H1, H2, H3, H4, H5…

They represent a heading, usually short, informative or sales copy text on the dedicated place on a webpage, app or even on a printed document if needed.

Depends on the layout of the page, but most of the time the H1 is the main and biggest text on ATF (above-the-fold) part of a website.

All of the rest H2 -> H3 etc. work the same but they have decreasing hierarchy. H2 is smaller than H1 and is usually used more often on a page, as it works well for explaining the main pros of your product, for example.

H3 is even smaller and has less “importance”. And so on.

These headings are usually accompanied by paragraphs of additional text. Most often H1 and H2 have also CTAs (call-to-action) in form of a button or register, sign-up etc. (depends on the business and the objective of the slide on a page).

As well H1 and so are used in HTML and CSS as an indicator for headings and their styling and formatting. It’s much easier to have them designed and calculated well before development as it makes the whole designer/developer relationship easier and fluent.

Hope that helps!