The <header> element represents introductory content for its nearest ancestor sectioning content or sectioning root element. A <header> typically contains a group of introductory or navigational aids.
Note: The header element is not sectioning content; it doesn’t introduce a new section.
<header>
<p>Welcome to...</p>
<h1>Voidwars!</h1>
</header>
In this example, the <article> has a <header>.
<article>
<header>
<h1>Flexbox: The definitive guide</h1>
</header>
<p>The guide about Flexbox was supposed to be here, but it turned out Wes wasn’t a Flexbox expert either.</p>
</article>