That's right, this website right here is all made out of HTML code. HTML can be very easy to do once you practice it yourself. For me, I spent a month in my summer to learn HTML and I still learn stuff today because of the new stuff that comes out every so often.
Now HTML has been around for a while, and it is growing popular as the years go by. HTML stands for Hyper Text Markup Language. An HTML file is a small file that contains tags for your web page. The tags tell the web browser how to display the page to everyone who sees it. Also, a HTML file must have an extension of .htm or .html on it. The great thing about HTML is that you can edit or make new HTML files using a simple text editor like Notepad.
If you want to learn more, go to W3 Schools HTML Basics to learn more about building web pages.