It stands for Hyper Text Markup language which is a very simple programming language, in which only thing we have to understand is the syntax and the meaning of the tag.
The very simple syntax of HTML is
<head><title>my first webpage</title></head>
Always remember that whenever you type the code in notepad and save it, it will be saved as a notepad file by default, to make it an HTML file we use the extension (.html) or (.htm).It will work both the ways.
Always remember, that tags start by <tag_name>and end with</tag_name>, the tag typed at first is to be ended at last, for example:-