Make my about page “about.html” instead of “/?page_id=2”

I’m actually a web developer but I’ve never messed with wordpress before. I can’t stand not being able to give pages permanent hand-chosen names for the URL. I want to be able to make all of my pages have real names like about.html, not a weird wordpress number.

I’m just talking about the pages, not blog posts or comments or anything like that.

Also, if anyone has some good resources for how I can learn to create my own themes, I’d love a link if you have time.