You might have a very good website with good content in it.If you want someone to visit your site or someone to use your content yout website should be listed in one or other search engines search results.But how will these search engines know about your website.Search engines use certain crawling algorithms to crawl any website on the web.Unless you disable crawling in your website ,it will index your website too.But it may take time.So the other go is you manully submitting your website to certain search engines.Here is the URLs to submit your website to some top search engines for free.
Suggestion : There will be many free site submission sites around the web asking gor your email Address.Forget abou the actual site sumbission ,these will unnecessarily populate your mail box daily.Better not go for them.