The HTML <head> tag represents the head section of the HTML document.
The <head> element can contain other HTML tags that contain metadata. Metadata provides information about the document such as title, description, keywords etc. A typical HTML document might contain a <title> tag, one or more <meta> tags, a <script> tag, and a <style> tag - all enclosed within the <head> element.
Most metadata are not displayed in the browser (although the title usually appears in the browser's title bar) but it can be useful for the functionality of the page.
The <head> tag is written as <head></head> with the metadata content enclosed between the start and end tags. The <head> tag is placed between the opening and closing <html> tags.
Most HTML documents must have a <title> tag within the <head> tag (the only exceptions are: if the document is an <iframe> srcdoc document or if title information is available from a higher-level protocol, for example in the case of an HTML formatted email).
Like this:
<!doctype html>
<html>
<head>
<title>Page title...</title>
</head>
<body>
Page body...
</body>
</html>
The profile attribute is not supported in HTML5.
To see more detail on the two versions see HTML5 <head> Tag and HTML4 <head> Tag. Also check out the links to the official specifications below.