You can use the .htaccess file to allow the execution of PHP code in simple HTML files.
First, set the folder in which the .htaccess file will be created, using the .htaccess location form at the top of the page. A click in the form field will open a pop-up window, from where you can browse to the desired website folder.
Then, go to the other options menu. In there, simply mark the Enable PHP code in HTML file checkbox. That’s everything.
To manually allow the execution of PHP code in HTML files, add the following handler in a .htaccess file: AddHandler fcgid-script .html .htm
Once you are done, scroll down to the bottom of the page and click the “Generate” button. The newly created .htaccess file will take effect in up to 15 minutes.