On the Internet, when web pages are indexed by search engines, this is called indexing. A web page is indexed when its content is marked by descriptors, i.e. search words. The descriptors are then captured by the search engine robots such as the Googlebot and added to the search engine database.
Only web pages that have been indexed by search engines can appear on the search engine results pages( SERP). At which position is decided by the ranking algorithm.
The faster the indexing by the search engines, the sooner the website can appear in the result lists. Since a quick appearance is often of particular interest for reasons of topicality, there is the procedure of immediate indexing, instant indexing. While normal indexing can take several weeks, instant indexing takes only a few minutes or hours.
The mere appearance of goolgebots are not necessarily a sign of indexing.