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

Then there is a header text, this is h1

This is h2

And this is h3

Each of them can be used in a lot of different ways. h1 is used mainly for text that you use as a heading. h2 is used as a “sub” category text usually for a small description of the H1. And 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.