Always use heading styles, tags or other formatting features for headings and sub-headings.
Why this matters...
Headings
A heading describes the content that follows it, serving as a valuable way for users to navigate through a page or document.
Heading Styles
Sighted users can quickly navigate using headings. When you use heading tags or styles it allows screenreaders to navigate in the same way.
Sub-Headings
Sub-headings help break content into smaller sub-sections. This breaks up large, overwhelming blocks of content and aids navigation.
Navigability is an important aspect of accessibility. If you have a large page or document, you should use headings and sub-headings to divide you content into meaningful chunks. A sighted user can easily skim a table of contents or series of visible headings to find relevant content. However, screenreaders cannot identify headings by size, colour, font or other formatting feature. For this reason, heading tags or styles are an important way to mark headings for screenreaders.