Virtual includes with XAMPP

I am running Ubuntu 18.04 with XAMPP 7.3.7.1 for Linux. I have one acct. that uses HTML and so I use `` for my includes. The problem is when I bring up the virtual host, it doesn't display any of the includes. I already have other sites that work but they use PHP. Any idea on how to fix this? If this has already been solved, point the way.