The source code of a simple html page is shown in the Source Code Box. Since HTML5, tag <!doctype html> at the very beginning part of a web page has been required to correctly render a html page with a variety of browsers. The tag also help you validate your web page with w3c standard.
The rest part of a web page should start with <html> and end with </html>. Between <html> and </html> tags, just like a human body, has tag <head> and <body>. You may put a title, such as “My page title”, in the head, which will appear in your browser’s title bar. You should put all your web page content between <body> and </body>.