There are a lot of different types of text when it comes to making a website. There’s the regular paragraph text I am using right now.

<h1>Then there is a header text, this is h1</h1>

Then there is a header text, this is h1

<h2>This is h2</h2>

This is h2

<h3>And this is h3</h3>

And this is h3

Each header type is used in a lot of different ways.
h1 is used mainly for a text that you use as a heading.
h2 is used as a “sub” category text, usually for a small description of the H1.
h3 is used as a sub-category for an h2. h3 is rarely used as most people use regular paragraph text, but you can use h3 if you want your text to be more visible.