Indexing is the step where Google keeps a copy of your page in its own records so it can be shown in search results. If a page is not indexed, it cannot rank for anything, no matter how good it is. It simply is not in the competition.
Crawled, indexed, ranked
Three different things, in order. Crawling is Google visiting the page and reading it. Indexing is Google deciding the page is worth keeping and filing it. Ranking is where it lands when somebody searches.
A page can be crawled and not indexed. Google says so plainly in Search Console, with a status along the lines of crawled but currently not indexed, which usually means it looked at the page and did not think it was worth storing yet.
Why a new site takes time
A brand new site has nothing pointing at it and no history, so Google is in no hurry. A few pages get indexed in days. The rest can take weeks, and the pattern is unpredictable rather than a neat queue.
You can help it along. Submit a sitemap, get your Google Business Profile live with the website link on it, and make sure every page is reachable by clicking from the homepage. Requesting indexing in Search Console works for one page at a time and is not a shortcut for a whole site.
A worked example
A firm launches with eight town pages and cannot understand why only three show up in Google after a month. In Search Console, the other five say discovered but not currently indexed.
The five are the ones written thinly by swapping the town name. Once they are given real local detail and a photo of a job in that town, they get indexed over the following weeks. The problem was never the launch, it was the pages.