HTML provides six levels of heading elements, <h1> through <h6>, establishing the document's architectural outline. The <h1> represents the main page title. It is critical for accessibility and SEO to use headings sequentially without skipping levels (e.g., don't jump from <h2> directly to <h4>).

Screen readers rely heavily on this predictable outline to allow visually impaired users to navigate the document structure. Treat headings as an ordered table of contents, not as a shortcut to make text visually larger.

HTML offers precise semantic lists to group related data sets. Unordered lists (<ul>) are utilized when the exact sequence of items is structurally irrelevant, automatically rendering with simple bullet points.

In contrast, Ordered lists (<ol>) are strictly reserved for sequential instructions where the order matters significantly, rendering numbered steps. Within both structures, every individual item must be explicitly wrapped in a List Item (<li>) tag.

Modern web architecture heavily distinguishes between how text *looks* visually and what it *means* semantically. The <strong> element explicitly dictates strong logical importance, typically rendering as bold.

The <em> element indicates stress emphasis within a sentence, typically rendering as italics. Screen readers actively change their vocal inflection when processing these tags. If you just want text to visually look bold without conveying structural importance, use CSS instead.

HTML includes specialized inline elements for specific data patterns. To display dynamic edits over time within an application, you should pair the <del> (deleted text) tag with the <ins> (inserted text) tag. This communicates a state change, such as a price drop.

Additionally, the <mark> tag explicitly highlights text for visual reference, and the <small> element represents side comments, such as copyright notices or legal disclaimers, effectively reducing their semantic weight.