On page SEO basically to set the best keyword for your website through their coding. Set best keyword which is related to your content. If your site have god keywords, chance to increase its ranking will more.

Search Engine Optimisation is a technique to increase the traffic as well as ranking in google search engine. It could be off page and on page. Off page consist many thing like directory, forum, bookmarking, article post, blog post, ppt submission etc and In on page, web site's coding will change by setting best keyword.

Onpage optimization refers to all measures that can be taken directly within the website in order to improve its position in the search rankings.