Search engine optimization ( SEO ) is the art and science of getting pages to rank higher in search engines such as Google. Because Search rank is one of the main ways to aid people to discover content online, ranking, higher leads to higher Website traffic. 

Seo is by far the most important tool needed by anyone who has a website, online shops or content, as SEO involves the improvement of quality and quantity of traffic the website or online shop has on a day to day basis.
 

Usually, SEO targets unpaid traffic rather than prepaid traffic. As it works on generally focuses on organic traffic and rank on search engines.