Search engine optimization is a methodology of strategies, techniques and tactics used to increase the amount of visitors to a website by obtaining a high-ranking placement in the search results page of a search engine (SERP) - including Google, Bing, Yahoo and other search engines.
It is common practice for Internet users to not click through pages and pages of search results, so where a site ranks in a search is essential for directing more traffic toward the site. The higher a website naturally ranks in organic results of a search, the greater the chance that that site will be visited by a user.
SEO helps to ensure that a site is accessible to a search engine and improves the chances that the site will be found by the search engine. SEO is typically a set of "white hat" best practices that webmasters and Web content producers follow to help them achieve a better ranking in search engine results.
You can go to Google and search any term about SEO, you will get the results as you want to learn.
Good luck to you,