The <header> tag is responsible to hold the information about header of HTML document. Especially it contain title, heading and navigation links of the document.
Example of Code
<html>
<head>
<title></title>
</head>
<body>
<header>
<h1>HTML</h1>
<p>Hypertext Markup Language</p>
<a href="http://schools.inimisttech.com/tutorial/topic/Html">Learn HTML</a>
</header>
</body>
</html>
Output
HTML
Hypertext Markup Language
Learn HTML