Search engine submission is how a webmaster submits a website directly to a search engine. While Search Engine Submission is often seen as a way to promote a web site, it generally is not necessary because the major search engines like Google, Yahoo, and Bing use crawlers, bots, and spiders that eventually would find most web sites on the Internet all by themselves.
There are two basic reasons to submit a web site or web page to a search engine. The first reason would be to add an entirely new web site because the site operators would rather not wait for a search engine to discover them. The second reason is to have a web page or web site updated in the respective search engine.