Indexed pages are those webpages of a website that a search engine has crawled through, analysed and added accurately to its database of webpages. Indexing is a key stage that a webpage must go through if it’s to be listed on search engine results pages (SERPs).
There are two ways that a webpage will come to be indexed. First, a webmaster can request that a search engine crawls their website’s pages, adding them to the search engine’s database. Second, these pages will be found automatically, after a brief period of time. These discoveries happen regularly when a search engine crawler happens upon a new website or set of webpages.