Search engines can find and crawl your site even if you don't submit it to them (unless you tell them not to), but it could take a while.  Additionally, it's a good idea to submit a sitemap to be sure they're aware of all your pages. 

We can submit a sitemap along with your website to the major search engines.  You also get feedback to help verify the status of your submission as well as qualities of various aspects of your website.