How to set the time zone with php

im trying to set the time in PHP but i don’t know to set the time zone.

<?php
   $currentDateTime = time();
   $newDateTime = date('h:i A', strtotime($currentDateTime));
?>
<input type="text" name="time" value="<?php echo $newDateTime; ?>">

>Solution :

You can do this by adding the following code:

<?php

date_default_timezone_set('Africa/Johannesburg');
echo date('H:i:s', time());

?>