Dynamically Creating Pages

So here's a funny story...recently I was trying to use PhP inside a page I have created dynamically. I was just using simple echo statements to try to output HTML to the page. Seems simple right? For some reason I couldn't figure out it just wasn't working. So I did a lot of research on single quotes and double quotes and PhP functions such as htmlspechialchars() and addslashes(). None of those worked. Then I decided to look at the function that was creating the page. Turns out it was creating a .HTML page and not a .php page so it could not read the PhP. I felt foolish after that. Anyway I learned some things I would have to deal with later so it wasn't a complete waste of time.