The PageRank method was named after Larry Page, one of Google's founders, to determine a website’s popularity and quality, two factors that affect its place on a search engine results page. The paper was authored by both Google founders. PageRank is actually an algorithm used on data collected by Googlebot whilst crawling websites. The program or "bot" looks at the HTML (HyperText Markup Language) and other code that websites are written in.
The algorithm assigns data values to linked web documents and it can be performed on the gathered website data iteratively, more than once, or algebraically in order to derice an accurate figure.
Some examples that demonstrate how PageRank works:
If Website A has a high page rank and is linked to Website B then Website B will, by association, have also have a high page rank.
PageRank was one of the first metrics used by Google. Nowadays, however, over 200 signals are used for determining a webpage's position in the search engine results, based on the search query entered by a web user.