Meta Elements for HTML

<!DOCTYPE html>
This is used at the beginning of every HTML document. It is not technically HTML, but rather informs the browser of what kind of document to expect. It is for HTML5 specifically, as the other versions of HTML4 and XHTML use their own designation.

<HTML> ... </HTML>
This is the Element emcompasing all the HTML within the document.

<HEAD> ... </HEAD>
The HEAD Element is used to separate the header informaton from the main body of the document. The text within the HEAD tags does not appear within the document. HEAD is used to contain the tags TITLE, LINK, STYLE, META, and more.

<BODY> ... </BODY>
The BODY tag is used to isolate the content of the webpage. Everything that will show up on the webpage is contained within the BODY tags.