$_POST is an associative array of variables passed to the current script via the HTTP POST method.
<?php $_POST['name'] = "Michael"; echo 'Hello ' . htmlspecialchars($_POST['name']) . '!'; ?>
You can try to run the script here.
The output in the browser will be:
$_POST is mainly used in form processing. It is an associative array and so we can pass the name Michael using $_POST[‘name’].