The HTML document <html> element is used to defined the whole html document.
Example:
<html>
<!--Tag define to the whole html document-->
<body>
</body>
</html>
The head <head> element is used to define the head of the document. The <title> element is always in the <head> element. The elements in the other elements are called nested elements.
Example:
<html>
<head>
<!--The title element is nested in element <head> -->
<title>The page title</title>
<!--The title element is nested in element <head> -->
<title>The page title</title>
</head>
<body>
<body>
</html>
The body <body> element defines the body of your web page.
Example:
<html>
<head>
<title>The page title</title>
</head>
<body>
Content Here!
</body>
</html>