Why it matters
Plenty of "why don't we rank" mysteries are really "we're not indexed" problems: a stray noindex tag, a blocked section, pages the crawler can't reach. These failures are silent: the site looks fine to humans while being partially invisible to engines.
How it works
Crawlers follow links and sitemaps to find URLs, fetch and render the pages, and decide what deserves indexing based on quality, uniqueness and directives you control (robots rules, noindex, canonicals). Search Console shows you exactly what got crawled, indexed, or excluded and why.
What to do about it
Open Google Search Console's page-indexing report. The "excluded" reasons list is your technical SEO to-do list, in priority order, for free.
