1. Search Engines do 2 things: Crawl & Index.
So, what does that mean? First, Moz.com compares a search engine crawling your site to a subway, everything is connected. They will investigate your content, going from page to page, checking links, images, paths, load times, and everything else. Second, indexing is simply the rank that Google or other search engines give your website based on relevance and popularity for any given phrase or keyword that is searched for by a user.