Indexing is processing a page and possibly adding it to a search engine's database. A discovered or downloaded URL isn't automatically stored and shown in results.
What is indexing?
After crawling, Google analyzes the content, links, metadata, duplicates and other signals. For a JavaScript page, rendering can be part of the process too.
Google then picks the canonical version and decides whether to add the page to the index. Even an indexed page has no guaranteed ranking or appearance for a given query.
How a page gets into the index
The URL has to be accessible, return an appropriate status code and carry no valid noindex directive. Internal links, the sitemap, the content and a consistent canonical matter as well.
Requesting indexing in GSC can speed up the check of a single URL, but it doesn't guarantee inclusion. On a larger site, fix the systemic cause. Submitting every page by hand won't scale.
Why Google sometimes doesn't index
- The URL has a
noindexor isn't accessible. - Google picked a different canonical version.
- The page is a duplicate or adds little value.
- Important content doesn't render or needs an interaction.
- The URL has no internal links and its role isn't clear.
Start with URL Inspection in Google Search Console. Compare the result with the HTTP response, the HTML, the canonical, robots.txt and the internal links.