Technically, each HTML document should be enclosed within the <HTML> container. Within this container should be the <HEAD> container and the <BODY> container. In other words, it should look like this:
<HTML> <HEAD> (header info goes here) </HEAD> <BODY> (text goes here) </BODY> </HTML>
The <BODY> container contains everything you see in the browser window. The <HEAD> container contains header information about the page - information the software uses and the user doesn't. For example, the page title goes in there; it is enclosed in the <TITLE>...</TITLE> tags. That is a basic summary of page structure.