Heading Style Levels Are the Pillars and Beams of Document Structure

Headings (H1–H6) are not decorations for dressing up a document's appearance, but structural elements that hierarchically divide the body text. When you gather the headings together, you get a TOC (Table of Contents), and the relationships between sections become clear.

In web documents, this role carries over to HTML's h tags and p tags. Headings are handled with h1 through h6, and body text with p tags as the default, and Markdown corresponds to almost the same structure.

The key point is managing the order and level of heading styles, not their visual appearance. In particular, a flow where descending levels drop by only 0 to 1 level at a time, while ascending levels can rise relatively freely, makes the document structure stable.

Conversely, overusing horizontal rules (hr) below headings prevents the heading and body text from being connected as one cohesive unit, and blurs the document's semantic structure. If you need an underline-like effect, it should be handled with CSS, not HTML structure.

Finally, SEO is not a major consideration for most internal documents. For meeting minutes, reports, and work documents, document consistency and readability matter more than search engines, so consistently maintaining the heading hierarchy is far more practical than debating the number of H1s.