How can PHP be used to simulate iframes for including external content like forums in a webpage?

To simulate iframes for including external content like forums in a webpage using PHP, you can use the `file_get_contents()` function to fetch the external content and then echo it within your webpage. This allows you to include external content seamlessly without using iframes.

<?php
$external_content = file_get_contents('https://example.com/forum');
echo $external_content;
?>