An on-page SEO audit is a page-by-page review of the elements search engines and readers use to judge a page's relevance and quality: title tags, meta descriptions, heading structure, content depth and keyword alignment, internal linking, image optimization, and URL structure.
Unlike a technical audit, which focuses on crawlability and site infrastructure, an on-page audit looks specifically at what's actually written and structured on the page itself — the parts most directly within a content team's control to fix.