If you have a website and a menu which is dynamically built using PHP, you could only use it on PHP pages.
Example:
You have menu.php and all the pages of your site: index.php, services.php, portofolio.php, contact.php
Using the following script you will be able to access the contents of all your pages using a HTML extension.
The .htaccess file starts here
RewriteEngine on
RewriteBase /
RewriteRule ^(.*)\.html$ $1.php [L]
Also You have to change all the links through out the website from the PHP extension to HTML.
Your visitors can now access the contents of services.php using services.html
Using this htaccess basic PHP to HTML rewrite rule you can present PHP files as HTML.