insert heading tag in a tag code example

Example 1: how to write heading tag tag in html

<h1>Biggest<h1>
<h2>Pretty Big<h2>
<h3>Medium<h3>
<h4>Pretty Small<h4>
<h5>Very Small<h5>
<h6>Smallest<h6>

Example 2: html heading tag

<h1> The biggest heading size </h1>
<h6> The smallest heading size </h6>