H1 tags are one of the most important things on the page. Imagine your page as a newspaper, your H1 tag is like the headline of a newspaper. Your H1 tag should contain keywords that are unique and targeted to the page they’re on. It must also be concise and straight to the point.
Subheadings (H2, H3, H4 and so one) provide structure to your page. H2 is for subheadings of your H1. We use it to divide content into understandable blocks. Search engines like Google and your visitors will like it.
Best SEO practice is you should have one H1 tag at the top of the page for your main headline because search engines look for this, then H2, H3, and so on through the page for subheadings that help break up the text in natural places.
Also, headings are intended in HTML as short pieces of text (less than a sentence) to break up a page into sections. This is why Google regards them well for SEO: it can determine the topics on a page. If a heading is written longer, like a few sentences or even a paragraph of text, it will likely be ignored by Google for SEO since it does not fit with what a heading is intended for. All headings should be brief but comprehensive.