When we have to need to change the date format we are the use of the PHP date format. See below here some example of diplay the date using the date format.

echo date("Y-m-d h:i:s");

see below output here.

2019-02-20 22:05:10


See below required specific string character for the date format.

Type Character Description
Date d day of the month, 2 digits with leading zeros; i.e. '01' to '31'
  j day of the month without leading zeros; i.e. '1' to '31'
Day D day of the week, textual, 3 letters; i.e. 'Fri'
  l day of the week, textual, long; i.e. 'Saturday'
  w day of the week, numeric, i.e. '0' (Sunday) to '6' (Saturday)
  z day of the year; i.e. '0' to '365'
  r RFC 822 formatted date; i.e. 'Thu, 21 Dec 2000 16:01:07 +0200' (added in PHP 4.0.4)
  S Suffix for day of the month in 2 chrs ( with j )
  z Day of the year ( from 0 to 365 )
Month m month; With leading zeros; i.e. '01' to '12'
  n month without leading zeros; i.e. '1' to '12'
  M month, textual, 3 letters; i.e. 'Jan'
  F month, textual, long; i.e. 'January'
  t Number of days in the month ( 28 to 31 )
Year L 1 for Leap year, 0 if not
  o ISO-8601 week-numbering year.
  Y year, 4 digits; i.e. '2018'
  y year, 2 digits; i.e. '19'
Hour g hour, 12-hour format without leading zeros; i.e. '1' to '12'
  G hour, 24-hour format without leading zeros; i.e. '0' to '23'
  h hour, 12-hour format; i.e. '01' to '12'
  H hour, 24-hour format; i.e. '00' to '23'
Minutes i minutes; i.e. '00' to '59'
Seconds s seconds; i.e. '00' to '59'
  a 'am' or 'pm'
  A 'AM' or 'PM'
  B Swatch Internet time
  I '1' if Daylight Savings Time, '0' otherwise.
  L boolean for whether it is a leap year; i.e. '0' or '1'
  T Timezone setting of this machine; i.e. 'MDT'
  U seconds since the epoch
  Z timezone offset in seconds (i.e. '-43200' to '43200'). The offset for timezones west of UTC is always negative, and for those east of UTC is always positive.
  e, O, P and T timezone identifier ( e ) , difference in Hour and minutes to GMT (O),+- Hour : Minute (P), Short name of zone ( IST) (T)