What is the difference between using include() and a normal link to call a HTML file from a PHP file?

When using include() in PHP to call a HTML file, the contents of the HTML file are directly inserted into the PHP file at the point where the include() function is called. This means that any PHP code within the HTML file will be executed. On the other hand, using a normal link to call a HTML file will simply redirect the user to the HTML file without executing any PHP code within it.

<?php
// Using include() to call a HTML file
include('file.html');

// Using a normal link to call a HTML file
echo '<a href="file.html">Click here to view the HTML file</a>';
?>