date_default_timezone_set("Asia/Kolkata"); // List of Supported Timezones https://www.php.net/manual/en/timezones.php
date_default_timezone_set('America/Los_Angeles');
date_default_timezone_set(timezone)
date_default_timezone_set("Asia/Bangkok"); echo date_default_timezone_get();
<?php $date = new DateTime("now", new DateTimeZone('America/New_York') ); echo $date->format('Y-m-d H:i:s');