Search Enginr Optimization (SEO) is the process of optimizing your website around certain keywords helping it rank as high as possible on search engines.
When people search the products and services that you sell, they will be able to easily see your site and buy from you. SEO when done correctly shows your product and service pages on page one of Google.
Very few people go to the second page of Google while searching for anything. In fact, Google does not like this and would prefer people to get their answers quickly on page one. Hence, they ensure that the websites that are on page one answer all the questions.