Header 4 tags, known as H4 Tags are meant to serve as sub headers to your page’s content.
They are the fourth largest & 4th boldest of all tags.
Search Engines do not limit the amount of H4 tags they will honor, and they are considered 6th highest in priority (after URL, Title Tag, H1 Tag, H2 Tag & H3 Tag) for the keywords contained in them.
Search engines will honor the first 80 characters contained in each & traditionally the higher up on the page that a tag occurs the more value will be given to its keywords in terms of importance.
H4 Tags & Their Impact On Search Engine Optimization
H4 Tags are used to call out smaller bits of information in a page’s content that contain important keywords.
This can be things like the title of a graph, a heading for a phone number that contains which country’s office it dials to, or a sub-product/service that is relevant to the page’s primary theme, but maybe not what the page is focused on.
They can also be used to show variations of a product/service that may be less frequently searched for, but that a user may still want to see.
Always conduct proper keyword research before creating an H4 tag for site content.