Header (or Heading) Tags (HTML heading, HTML Header tags) and subheading tags are critical components of search engine marketing.
Optimally, page titles should also be included to clearly define the page’s purpose and theme. All of the header tags should be used according to their relevance.
The most important tag is the <h1> heading tag, and will usually be the title of a page/post. Heading tags have hierarchy from <h1> to <h6>.
Header Tags are used to differentiate the headings and sub-headings of a page from the rest of the content, and It has an impact on both the SEO and usability of your site.
There are things you shouldn’t be doing with heading tags: Do not stuff them with keywords, not more than one h1 tag on a page, no heading tags in hidden text, different heading tags on different pages etc.