Pages may not be indexed because Google cannot crawl them, they are blocked by robots.txt, they contain a noindex directive, they are canonicalized to another URL, they are duplicates, they have very thin content, or Google has not found enough value to include them. Indexing is not guaranteed simply because a page exists. The right diagnosis starts with Google Search Console’s URL Inspection Tool, sitemap status, internal linking, canonical tags, robots directives, and content quality. Fixing indexation requires both technical access and a reason for the page to deserve inclusion.
Example
If a city page says nearly the same thing as twenty other city pages, Google may crawl it but decide not to index it. Improving unique local value, proof, reviews, photos, service details, and internal links can help.