diff --git a/src/date-util/date-util.spec.ts b/src/date-util/date-util.spec.ts
index eea4d50..3540427 100644
--- a/src/date-util/date-util.spec.ts
+++ b/src/date-util/date-util.spec.ts
@@ -4,7 +4,11 @@ import {
   durationTo,
   endOfByTimezone,
   formatDate,
+  formatInIso8601,
   fromNow,
+  getDateString,
+  getDatetimeString,
+  getTimestampString,
   getTimezoneOffsetInHours,
   isAdult,
   isLastDateOfMonth,
@@ -19,6 +23,7 @@ import {
 } from './date-util';
 import {
   DATE_FORMAT,
+  DATETIME_FORMAT,
   DATETIME_FORMAT_WITH_MILLIS,
   TIMESTAMP_FORMAT,
   TIMEZONE_PST,
@@ -482,6 +487,49 @@ describe('format', () => {
   });
 });
 
+describe('formatInIso8601', () => {
+  it('should return formatted date string in ISO format string', () => {
+    const testDatetime = new Date(testDatetimeStr8);
+    expect(formatInIso8601(testDatetime, { format: DATE_FORMAT })).toEqual(testDateStr);
+    expect(formatInIso8601(testDatetime, { format: DATETIME_FORMAT })).toEqual(testDatetimeStr5);
+    expect(formatInIso8601(testDatetime, { format: DATETIME_FORMAT_WITH_MILLIS })).toEqual(testDatetimeStr8);
+  });
+  it('should return formatted date string of local time', () => {
+    const testDatetime = new Date(testDatetimeStr8);
+    expect(formatInIso8601(testDatetime, { format: DATETIME_FORMAT, isUtc: false, timeZone: 'Asia/Seoul' })).toEqual(
+      `2022-02-23T10:23:45+09:00`
+    );
+    expect(formatInIso8601(testDatetime, { isUtc: false, timeZone: 'PST8PDT' })).toEqual('2022-02-22T17:23:45-08:00');
+  });
+});
+
+describe('getDateString', () => {
+  it('should return formatted date string', () => {
+    expect(getDateString(new Date(testDatetimeStr8))).toBe(testDateStr);
+  });
+  it('should return formatted date string of local time', () => {
+    expect(getDateString(new Date(testDatetimeStr6), false)).toBe(testDateStr);
+  });
+});
+
+describe('getDatetimeString', () => {
+  it('should return format datetime string', () => {
+    expect(getDatetimeString(new Date(testDatetimeStr8))).toBe(testDatetimeStr5);
+  });
+  it('should return formatted datetime string of local time', () => {
+    expect(getDatetimeString(new Date(testDatetimeStr8), false)).toBe('2022-02-23 10:23:45');
+  });
+});
+
+describe('getTimestampString', () => {
+  it('should return formatted timestamp string', () => {
+    expect(getTimestampString(new Date(testDatetimeStr8))).toBe(testTimestampStr);
+  });
+  it('should return formatted timestamp string of local time', () => {
+    expect(getTimestampString(new Date(testDatetimeStr8), false)).toBe('20220223102345678');
+  });
+});
+
 describe('durationTo', () => {
   it('시간을 초로 바꾸어 리턴한다.', () => {
     expect(durationTo('09:10:30')).toEqual(33030);
diff --git a/src/date-util/date-util.ts b/src/date-util/date-util.ts
index 0b5950f..dba532e 100644
--- a/src/date-util/date-util.ts
+++ b/src/date-util/date-util.ts
@@ -2,6 +2,7 @@ import { LoggerFactory } from '../logger';
 import { DatePropertyType, DateType, TimeZoneType } from './date-util-base.type';
 import {
   ADULT_AGE_DEFAULT,
+  DATE_FORMAT,
   DATETIME_FORMAT,
   LOCAL_DATETIME_FORMAT,
   ONE_DAY_IN_MILLI,
@@ -14,7 +15,7 @@ import {
   TIMESTAMP_FORMAT,
 } from './date-util.const';
 import type { TimeAnnotationSet } from './date-util.interface';
-import type { CalcDatetimeOpts, DatetimeFormatOpts } from './date-util.type';
+import type { CalcDatetimeOpts, DatetimeFormatOpts, IsoDatetimeFormatOpts } from './date-util.type';
 
 const timeZoneMap: Record<TimeZoneType, number> = { 'Asia/Seoul': 540, 'Asia/Tokyo': 540, PST8PDT: -480, UTC: 0 };
 const logger = LoggerFactory.getLogger('pebbles:date-util');
@@ -372,6 +373,61 @@ export function formatDate(d: Date, opts?: Readonly<DatetimeFormatOpts>): string
   });
 }
 
+/**
+ *
+ * @description It converts `date` in `opts.format` if it's given. Otherwise the default format would be `YYYY-MM-DDTHH:mm:ssZ`.
+ * - Other format options can be `YYYY-MM-DD` or `YYYY-MM-DDTHH:mm:ss.SSSZ`.
+ */
+export function formatInIso8601(date: Date, opts?: Readonly<IsoDatetimeFormatOpts>): string {
+  const formatOpts: IsoDatetimeFormatOpts = opts ?? {};
+  formatOpts.format = opts?.format ?? DATETIME_FORMAT;
+  return formatDate(date, formatOpts);
+}
+
+/**
+ *
+ * @description It converts `date` in `YYYY-MM-DD` format.
+ */
+export function getDateString(date: Date, isUtc = true, timeZone: TimeZoneType = 'Asia/Seoul'): string {
+  return formatDate(date, { format: DATE_FORMAT, isUtc, timeZone });
+}
+
+/**
+ *
+ * @description It converts `date` in `YYYY-MM-DDTHH:mm:ssZ` format if isUtc is true by default.
+ * Otherwise the format would be `YYYY-MM-DD HH:mm:ss`.
+ */
+export function getDatetimeString(date: Date, isUtc = true, timeZone: TimeZoneType = 'Asia/Seoul'): string {
+  return formatDate(date, { isUtc, timeZone });
+}
+
+/**
+ *
+ * @description It converts `date` in `YYYYMMDDHHmmssSSS` format.
+ */
+export function getTimestampString(date: Date, isUtc = true, timeZone: TimeZoneType = 'Asia/Seoul'): string {
+  return formatDate(date, { format: TIMESTAMP_FORMAT, isUtc, timeZone });
+}
+
+/**
+ *
+ * @description It converts `totalSeconds` in `hh:mm:ss` format.
+ */
+export function getTimeStringFromSeconds(totalSeconds: number): string {
+  if (totalSeconds < 0) {
+    throw new Error('Invalid number');
+  }
+
+  const seconds = totalSeconds % 60;
+  const totalMinutes = (totalSeconds - seconds) / 60;
+  const minutes = totalMinutes % 60;
+  const hh = String((totalMinutes - minutes) / 60).padStart(2, '0');
+  const mm = String(minutes).padStart(2, '0');
+  const ss = String(seconds).padStart(2, '0');
+
+  return `${hh}:${mm}:${ss}`;
+}
+
 export function durationTo(duration: string, unitType: DatePropertyType = 'second'): number {
   if (unitType !== 'second') {
     throw new Error('Not supported yet');
diff --git a/src/date-util/index.ts b/src/date-util/index.ts
index 80055db..5f13c57 100644
--- a/src/date-util/index.ts
+++ b/src/date-util/index.ts
@@ -6,7 +6,12 @@ export {
   endOfByTimezone,
   format12HourInLocale,
   formatDate,
+  formatInIso8601,
   fromNow,
+  getDateString,
+  getDatetimeString,
+  getTimestampString,
+  getTimeStringFromSeconds,
   getTimezoneOffsetInHours,
   getTimezoneOffsetString,
   isAdult,