An internet based tool that searches an index of documents a particular term, phrase or text specified by the user. Commonly used to refer to large web-based search engines that search through billion of pages on the internet . ON Page Optimization is a technique of SEO in which we done on the pages of the website OFF Page Optimization is a technique of SEO in which we covers activity that takes place else where(e.g. Link building )outside the website. In the OFF Page SEO we doesn’t change the website. We Change back Linking options .