Display my rendered out PHP in an HTML file

Here is what I am trying to accomplish.

I have a PHP that generates a page with a .php extension.

I want to take that output .php page and display it in an .html file.

For instance: when you view the source on the php file you see all the html that was created by the php page and not the php code in the php file. I need the new html file to contain nothing but html no php.

I hope that makes sense…

My dilemma is such:

My client wants this page to generate a PDF, Their server doesn’t have PHP 5+ (or else I’d just use dompdf…), so what I’m doing is just using a 3rd party html to PDF converter. It works great, but since I’m sending it a php page it tries to parse the PDF content and you get errors.