Definition and Usage of HTML <header> Tag as follows:
The <header> element represents a container for introductory content or a set of navigational links of the application.

In HTML5, A <header> element typically contains the following:

• one or more heading elements (<h1> - <h6>)
• logo or icon or Brand name
• authorship information

Note: You can implement several <header> elements in one HTML document. However, <header> cannot be placed within an another <header> element, <footer> or <address>.

An example of a header for an <article> is as follows:

<article>
 <header>
  <h1>Slight Book heading here</h1>
  <p>Posted by Chaitanya Kudumula</p>
  <p>Additional information here about Slight Book</p>
  </header>
  <p>Slight Book Interview Questions....</p>
</article>