diff --git a/docs/plugins/mapper-annotated-text.asciidoc b/docs/plugins/mapper-annotated-text.asciidoc
index e4141e98a2285..9b6eccd136696 100644
--- a/docs/plugins/mapper-annotated-text.asciidoc
+++ b/docs/plugins/mapper-annotated-text.asciidoc
@@ -167,8 +167,16 @@ duplicates removed. So:
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "text": {
         "type": "annotated_text",
@@ -215,8 +223,16 @@ are preserved.
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "text": { "type": "annotated_text", "store": true }
     }
diff --git a/docs/reference/mapping/fields/synthetic-source.asciidoc b/docs/reference/mapping/fields/synthetic-source.asciidoc
index 902b6c26611e5..f8666e2993d6a 100644
--- a/docs/reference/mapping/fields/synthetic-source.asciidoc
+++ b/docs/reference/mapping/fields/synthetic-source.asciidoc
@@ -2,7 +2,7 @@
 ==== Synthetic `_source`
 
 IMPORTANT: Synthetic `_source` is Generally Available only for TSDB indices
-(indices that have `index.mode` set to `time_series`). For other indices
+(indices that have `index.mode` set to `time_series`). For other indices,
 synthetic `_source` is in technical preview. Features in technical preview may
 be changed or removed in a future release. Elastic will work to fix
 any issues, but features in technical preview are not subject to the support SLA
@@ -11,15 +11,19 @@ of official GA features.
 Though very handy to have around, the source field takes up a significant amount
 of space on disk. Instead of storing source documents on disk exactly as you
 send them, Elasticsearch can reconstruct source content on the fly upon retrieval.
-Enable this by setting `mode: synthetic` in `_source`:
+Enable this by using the value `synthetic` for the index setting `index.mapping.source.mode`:
 
 [source,console,id=enable-synthetic-source-example]
 ----
 PUT idx
 {
-  "mappings": {
-    "_source": {
-      "mode": "synthetic"
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
     }
   }
 }
@@ -38,7 +42,7 @@ properties when used with synthetic `_source`.
 <<synthetic-source-fields-native-list, Most field types>> construct synthetic `_source` using existing data, most
 commonly <<doc-values,`doc_values`>> and <<stored-fields, stored fields>>. For these field types, no additional space
 is needed to store the contents of `_source` field. Due to the storage layout of <<doc-values,`doc_values`>>, the
-generated `_source` field undergoes <<synthetic-source-modifications, modifications>> compared to original document.
+generated `_source` field undergoes <<synthetic-source-modifications, modifications>> compared to the original document.
 
 For all other field types, the original value of the field is stored as is, in the same way as the `_source` field in
 non-synthetic mode. In this case there are no modifications and field data in `_source` is the same as in the original
@@ -227,10 +231,16 @@ For instance:
 ----
 PUT idx_keep
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": {
-      "mode": "synthetic"
-    },
     "properties": {
       "path": {
         "type": "object",
diff --git a/docs/reference/mapping/types/aggregate-metric-double.asciidoc b/docs/reference/mapping/types/aggregate-metric-double.asciidoc
index 8e14fba976360..8a4ddffc30bbd 100644
--- a/docs/reference/mapping/types/aggregate-metric-double.asciidoc
+++ b/docs/reference/mapping/types/aggregate-metric-double.asciidoc
@@ -267,8 +267,16 @@ For example:
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "agg_metric": {
         "type": "aggregate_metric_double",
diff --git a/docs/reference/mapping/types/boolean.asciidoc b/docs/reference/mapping/types/boolean.asciidoc
index 32f3d13edf581..494c41021dd2a 100644
--- a/docs/reference/mapping/types/boolean.asciidoc
+++ b/docs/reference/mapping/types/boolean.asciidoc
@@ -249,8 +249,16 @@ Synthetic source always sorts `boolean` fields. For example:
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "bool": { "type": "boolean" }
     }
diff --git a/docs/reference/mapping/types/date.asciidoc b/docs/reference/mapping/types/date.asciidoc
index ca2c23f932fc3..53b17a669ae75 100644
--- a/docs/reference/mapping/types/date.asciidoc
+++ b/docs/reference/mapping/types/date.asciidoc
@@ -130,7 +130,7 @@ The following parameters are accepted by `date` fields:
 <<ignore-malformed,`ignore_malformed`>>::
 
     If `true`, malformed numbers are ignored. If `false` (default), malformed
-    numbers throw an exception and reject the whole document.  Note that this
+    numbers throw an exception and reject the whole document. Note that this
     cannot be set if the `script` parameter is used.
 
 <<mapping-index,`index`>>::
@@ -248,8 +248,16 @@ Synthetic source always sorts `date` fields. For example:
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "date": { "type": "date" }
     }
diff --git a/docs/reference/mapping/types/date_nanos.asciidoc b/docs/reference/mapping/types/date_nanos.asciidoc
index 1a3b390b1690c..e9ec85c470ecf 100644
--- a/docs/reference/mapping/types/date_nanos.asciidoc
+++ b/docs/reference/mapping/types/date_nanos.asciidoc
@@ -160,8 +160,16 @@ Synthetic source always sorts `date_nanos` fields. For example:
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "date": { "type": "date_nanos" }
     }
diff --git a/docs/reference/mapping/types/flattened.asciidoc b/docs/reference/mapping/types/flattened.asciidoc
index 0a72ebc98ecef..af6ef3e739d0f 100644
--- a/docs/reference/mapping/types/flattened.asciidoc
+++ b/docs/reference/mapping/types/flattened.asciidoc
@@ -334,8 +334,16 @@ For example:
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "flattened": { "type": "flattened" }
     }
@@ -367,8 +375,16 @@ For example:
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "flattened": { "type": "flattened" }
     }
@@ -407,8 +423,16 @@ For example:
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "flattened": { "type": "flattened" }
     }
diff --git a/docs/reference/mapping/types/geo-point.asciidoc b/docs/reference/mapping/types/geo-point.asciidoc
index 6db05188dfb98..9ba8ea6e46782 100644
--- a/docs/reference/mapping/types/geo-point.asciidoc
+++ b/docs/reference/mapping/types/geo-point.asciidoc
@@ -229,8 +229,16 @@ longitude) and reduces them to their stored precision. For example:
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "point": { "type": "geo_point" }
     }
diff --git a/docs/reference/mapping/types/ip.asciidoc b/docs/reference/mapping/types/ip.asciidoc
index f068916478a78..f85dd78ecbd4a 100644
--- a/docs/reference/mapping/types/ip.asciidoc
+++ b/docs/reference/mapping/types/ip.asciidoc
@@ -170,8 +170,16 @@ Synthetic source always sorts `ip` fields and removes duplicates. For example:
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "ip": { "type": "ip" }
     }
diff --git a/docs/reference/mapping/types/keyword.asciidoc b/docs/reference/mapping/types/keyword.asciidoc
index a4be7026dffcd..b94216042427f 100644
--- a/docs/reference/mapping/types/keyword.asciidoc
+++ b/docs/reference/mapping/types/keyword.asciidoc
@@ -188,8 +188,16 @@ For example:
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "kwd": { "type": "keyword" }
     }
@@ -218,8 +226,16 @@ are preserved. For example:
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "kwd": { "type": "keyword", "store": true }
     }
@@ -248,8 +264,16 @@ For example:
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "kwd": { "type": "keyword", "ignore_above": 3 }
     }
diff --git a/docs/reference/mapping/types/numeric.asciidoc b/docs/reference/mapping/types/numeric.asciidoc
index d1e1c037e571e..5bfa1bc7c1240 100644
--- a/docs/reference/mapping/types/numeric.asciidoc
+++ b/docs/reference/mapping/types/numeric.asciidoc
@@ -259,8 +259,16 @@ Synthetic source always sorts numeric fields. For example:
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "long": { "type": "long" }
     }
@@ -287,8 +295,16 @@ Scaled floats will always apply their scaling factor so:
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "f": { "type": "scaled_float", "scaling_factor": 0.01 }
     }
diff --git a/docs/reference/mapping/types/range.asciidoc b/docs/reference/mapping/types/range.asciidoc
index 14c5b6098acbe..04341f68c630a 100644
--- a/docs/reference/mapping/types/range.asciidoc
+++ b/docs/reference/mapping/types/range.asciidoc
@@ -249,13 +249,21 @@ of official GA features.
 `range` fields support <<synthetic-source,synthetic `_source`>> in their default
 configuration. Synthetic `_source` cannot be used with <<doc-values,`doc_values`>> disabled.
 
-Synthetic source always sorts values and removes duplicates for all `range` fields except `ip_range` . Ranges are sorted by their lower bound and then by upper bound. For example:
+Synthetic source always sorts values and removes duplicates for all `range` fields except `ip_range`. Ranges are sorted by their lower bound and then by upper bound. For example:
 [source,console,id=synthetic-source-range-sorting-example]
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "my_range": { "type": "long_range" }
     }
@@ -316,8 +324,16 @@ For example:
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "my_range": { "type": "ip_range" }
     }
@@ -352,13 +368,21 @@ Will become:
 // TEST[s/^/{"_source":/ s/\n$/}/]
 
 [[range-synthetic-source-inclusive]]
-Range field vales are always represented as inclusive on both sides with bounds adjusted accordingly. Default values for range bounds are represented as `null`. This is true even if range bound was explicitly provided. For example:
+Range field values are always represented as inclusive on both sides with bounds adjusted accordingly. Default values for range bounds are represented as `null`. This is true even if range bound was explicitly provided. For example:
 [source,console,id=synthetic-source-range-normalization-example]
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "my_range": { "type": "long_range" }
     }
@@ -394,8 +418,16 @@ Default values for range bounds are represented as `null` in synthetic source. T
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "my_range": { "type": "integer_range" }
     }
@@ -429,8 +461,16 @@ Will become:
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "my_range": { "type": "date_range" }
     }
diff --git a/docs/reference/mapping/types/text.asciidoc b/docs/reference/mapping/types/text.asciidoc
index c33af69df5607..ca69c93e8f1a8 100644
--- a/docs/reference/mapping/types/text.asciidoc
+++ b/docs/reference/mapping/types/text.asciidoc
@@ -177,15 +177,23 @@ a <<keyword-synthetic-source, `keyword`>> sub-field that supports synthetic
 `_source` or if the `text` field sets `store` to `true`. Either way, it may
 not have <<copy-to,`copy_to`>>.
 
-If using a sub-`keyword` field then the values are sorted in the same way as
+If using a sub-`keyword` field, then the values are sorted in the same way as
 a `keyword` field's values are sorted. By default, that means sorted with
 duplicates removed. So:
 [source,console,id=synthetic-source-text-example-default]
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "text": {
         "type": "text",
@@ -233,8 +241,16 @@ are preserved.
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "text": { "type": "text", "store": true }
     }
diff --git a/docs/reference/mapping/types/version.asciidoc b/docs/reference/mapping/types/version.asciidoc
index 8da0fcae80fcd..1600451432bd8 100644
--- a/docs/reference/mapping/types/version.asciidoc
+++ b/docs/reference/mapping/types/version.asciidoc
@@ -63,16 +63,15 @@ The following parameters are accepted by `version` fields:
 [discrete]
 ==== Limitations
 
-This field type isn't optimized for heavy wildcard, regex or fuzzy searches. While those
-type of queries work in this field, you should consider using a regular `keyword` field if
-you strongly rely on these kind of queries.
-
+This field type isn't optimized for heavy wildcard, regex, or fuzzy searches. While those
+types of queries work in this field, you should consider using a regular `keyword` field if
+you strongly rely on these kinds of queries.
 
 [[version-synthetic-source]]
 ==== Synthetic `_source`
 
 IMPORTANT: Synthetic `_source` is Generally Available only for TSDB indices
-(indices that have `index.mode` set to `time_series`). For other indices
+(indices that have `index.mode` set to `time_series`). For other indices,
 synthetic `_source` is in technical preview. Features in technical preview may
 be changed or removed in a future release. Elastic will work to fix
 any issues, but features in technical preview are not subject to the support SLA
@@ -86,8 +85,16 @@ Synthetic source always sorts `version` fields and removes duplicates. For examp
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "versions": { "type": "version" }
     }
diff --git a/docs/reference/mapping/types/wildcard.asciidoc b/docs/reference/mapping/types/wildcard.asciidoc
index 79fc953051d54..89a3109a37164 100644
--- a/docs/reference/mapping/types/wildcard.asciidoc
+++ b/docs/reference/mapping/types/wildcard.asciidoc
@@ -141,8 +141,16 @@ Synthetic source always sorts `wildcard` fields. For example:
 ----
 PUT idx
 {
+  "settings": {
+    "index": {
+      "mapping": {
+        "source": {
+          "mode": "synthetic"
+        }
+      }
+    }
+  },
   "mappings": {
-    "_source": { "mode": "synthetic" },
     "properties": {
       "card": { "type": "wildcard" }
     }