Here is a quick example of PHP variable substitution:
<?php echo 2 + 2;
$myname = 'Perry';
?>
<h1>This page is all about <?php echo $myname ?></h1>
<?php echo 5 * 5 ?>
<h2>All About <?php echo $myname ?></h2>
The above code snippet assigns ‘Perry’ to the variable $myname, and then uses that variable in the h1 and h2 heading lines.