The headings test checks for appropriate use of headings in your page.
Semantically correct content is good for search engine optimisation and helps visitors without a visual browser access your content.
We check that you use headings in the right order (e.g. H1, then H2) and that no heading appears without a parent heading (i.e. you can't have a H2 without a H1).
Ensure that every page of your site uses headings in the right order, and that as a minimum, each has a H1.