how to get system date and time in php code example

Example 1: php get current date and time

$today = date("F j, Y, g:i a");   // October 30, 2019, 10:42 pm
$today = date("D M j G:i:s T Y"); // Wed Oct 30 22:42:18 UTC 2019
$today = date("Y-m-d H:i:s");     // 2019-10-30 22:42:18(MySQL DATETIME format)

Example 2: get current date from year input php

$date_input = '2003';
$date_output= date( "Y-m-d", mktime( 0, 0, 0, 1, 1, $date_input ));
//date_output = 2003-01-01