Search Engine Optimization (SEO) is the practice of guiding the design and development of a website so that it will naturally attract visitors by winning top rankings on the major search engines for selected search keyword phrases.
On-page optimization: It refers to factors that have an effect on your Website or Webpage listing in Natural search results.
Off Page Optimization: Off-page optimization refers to the ranking factors that are usually out of your control. The most important off - page factor is the links to your website (BACKLINKS). Link Buildings are Part of off Page.