on-page off-page

Keywords are intrinsically related to search terms – words and phrases that people enter into a search engine to find specific information. Most people enter 2 to 5-word phrases in Google to find what they are looking for. Google in turn analyzes all pages in its index and lists the pages which contain those search terms. Each web page usually contains one or two keywords that are repeated more often than others throughout the site. These keywords dictate the “theme” of a website.
In addition, Google analyzes other sites that contain links to your site. Specifically, Google looks to see if the text of a link (the clickable portion) that points to your site also contain those same keywords.
Page importance is all about links - their quantity, quality, and strength, which we will discuss later on. This part of the algorithm includes Google PageRank (PR).
Google looks for links that point to your site from other websites. Google believes a link from website A to website B is a “vote” for the importance of website B. In this way, other websites add votes for your website, which in turn helps increase a pages PageRank value on your site. Each page on your site has a PR value. Usually the PR value is the highest for the home page as most people will link to your home page rather than another page on your site.
The more web pages that link to your site, and the more important in turn those pages are, the more important Google thinks your site is and hence the higher your PageRank value. Moreover, it is the quality, as well as the quantity, of links that
matter – not all links are valued the same. Keep in mind that PageRank is but a single (albeit important) factor used in ranking.
Sites that are highly optimized for on-page factors can outrank sites that are less optimized but have higher PageRank.
PageRank value is assigned after comparing every page in the Google index against one another. This is billions and billions of web pages.
Note that PageRank does NOT factor in keywords or phrases used on your site.