why need seo?

now a days core of core website in the world.so we want to particular and right post about people want only one process SEO can help us this site to our goals.when we search any type article in google.bing.yahoo.etc search engine this search engine give to me or you whats you want.really we and any one cannot describe important of SEO so we should more practice SEO and our website to reach one of one position in the world