How the H1 works
The H1 is the top level of a page’s heading outline, and in almost every case it should name the subject of the page in the reader’s own language. It lives in the page itself, usually as the first thing below the header, and it is what a visitor reads to confirm they have landed where they meant to.
It is easily confused with the title tag, but the two do different jobs. The title tag is the line that appears in a search result and in the browser tab. The H1 is the line on the page. They often say similar things and they do not have to be identical: a search listing may need a location or a qualifier that would read awkwardly at the top of the page. On most WordPress themes the H1 is generated from the post title, so changing one changes both unless the theme keeps them separate.
Why the H1 matters
It is the fastest orientation a visitor gets. Someone arriving from a search result is checking, almost instantly, whether this page answers what they searched for. An H1 that echoes their language answers that; a vague or purely branded one sends them back to the results.
It matters more still for people using assistive technology, who frequently navigate by heading and rely on the H1 to establish the subject before anything else is read out. And because it normally sits at the top of the content, it is one of the plainest signals a search engine has about what the page covers — not a ranking control you can pull, but a clear statement of subject.
Common mistakes with the H1
Two errors dominate. The first is a missing or generic H1: a theme that puts the site name or the logo into the H1 on every page, so every page announces the same subject. The second is stuffing — packing several target phrases and a city name into one heading, which reads as machine-written to a person and achieves nothing for search.
The rule that a page may have only one H1 is often stated far more strictly than it deserves. Multiple H1s do not break a page or trigger a penalty; HTML permits them and Google has said they are not a problem. The reason to keep one is clarity, because an outline with a single top level is easier for a person and for assistive technology to follow. Treat it as good practice, not as something to panic about.
Getting it right
Write the H1 as a plain answer to the question what is this page, in the words a customer would use rather than internal jargon. If the page targets a particular term, that term usually appears by itself, because the page is genuinely about it. When it has to be forced in, the page and the term do not really match, and forcing the heading will not fix that.
Then check the site rather than the page. Crawl it, list every H1, and duplicates, blanks and site-name headings show up at once — almost always coming from a template rather than from individual pages, so one template fix clears the lot. Keep the relationship with the rest of the heading structure tidy, let the title tag do its own job in the search listing, and treat both as routine on-page work.