HTML stands for HyperText Markup Language, the language of the Internet's World Wide Web.
Title your main home page file "index.html", because this is the way almost all web servers are set up to handle. HTML documents look a lot like word-processing documents with the extension of .htm, .html, or .shtml. HTML documents have two parts, the head and the body. The head of the document contains the document's title. (The body contains everything else.)
The structure of the HTML document is:
Look at where is the title text: