The <header> tag in HTML is used to define the header for a document or a section. It contains information related to the title and heading of the related content. The <header> element is intended to usually contain the section’s heading (an h1-h6 element or an <hgroup> element), but this is not required.
The <header> element can also be used to wrap a section’s table of contents, a search form, or any relevant logos. The <header> tag is a new tag in HTML5 and it requires a starting tag as well as an end tag.
There can be several <header> elements in one document.
A <header> tag cannot be placed within a <footer>, <address> or another <header> element.
<header> Contents... </header>