The process of site crawling occurs when a search engine spider, (AKA Web Crawler, Robot, Bot, etc.) visits your website to gather information about it.
For a spider to access your page, it needs to find it through links. The link can be from your site or an external page.
It’s good practice to ensure that your internal link structure includes every page on your site. Search engine spiders can then crawl your entire site, and add each page to the search index.
Here’s Our Collection of Pages on Site Crawling.