Headings are used to format content. While not necessarily always true, the higher number of heading means that the content is smaller, with H1 tags being the main title for any page. Without an H1 tag, a site will rank lower with Google, as not seeming to have a clear purpose or sentence to categorize it. Commonly a website will have between h1 all the way to an h7 tag to categorize headings throughout the site. The most commonly used form of text is the paragraph, which is just a p.
<h1>Draw The Owl</h1> <h2>Draw The Owl A bit Smaller</h2> <h3>Draw Even Smaller</h3> <p>Paragraph Owl</p>
Draw The Owl

Draw The Owl A Bit Smaller

Draw Even Smaller

Paragraph Owl

Creating a Heading

Draw The Owl