Header tag is used to defined heading of a document in HTML, there are six types of header tag are, h1, h2, h3, h4, h5 and h6.

Syntax of writing header tag are as below,

<h1> Heading 1 </h1>

<h2> Subheading 2 </h2>

<h3> Subheading 3 </h3>

<h4> Subheading 4 </h4>

<h5> Subheading 5 </h5>

<h6> Subheading 6 </h6>