What does Heading Tags mean?
Heading tags are the HTML elements h1 to h6 used to mark headings. They describe the document structure; the visible font size is styled separately.
AN EXAMPLE IN PRACTICE
Where you might encounter it
The H1 names a page’s main topic, H2 divides it into sections, and H3 subdivides those sections. A small line about a service can technically be the H1 even if the slogan appears larger visually.
Further sources
From NetzTurm Decode. Clear explanations with historical context.