<h1–h6>
Six levels of section headings that form the document outline screen readers and crawlers navigate by.
Baseline: Widely available · Sectioning & landmarks
When to use it
One h1 per page; pick each level by outline depth, descending one step at a time.
When not to
Never choose a level for its font size, never skip levels going down, and never fake a heading with bold text.
Key attributes
id- anchor target for deep links
Example
<h1>The page topic</h1>
<h2>A chapter</h2>
<h3>A subsection</h3>