If you do not have a web host, you can always allow the registrar to park your domain name at a temporary website specially set up for you. This way you can quickly secure your domain name before it's too late and still take your time to set up the other aspects of your site. As far as I can tell, most registrars (or probably all) automatically park your domain by default whether you ask them to or not, so if this is your situation, you probably don't have to do anything special to get it done. Some of those registrars also provide you with a free email address at your own domain name while it is parked at their site, like firstname.lastname@example.org (where "example.com" is your domain).
The suffix identifies the name as belonging to a specific top-level domain (TLD). As of late 2016, when this article was written, there are numerous TLDs available for general purchase, including .com, .edu, .game, .green, .hiphop, .net, and .org. The most popular of these by far is .com, which is supposed to indicate commercial sites, but in reality has come to include almost everything.
A great domain name is a concise, easy to type, and memorable URL that reflects your brand or your website’s subject matter. Avoid using hyphens, strings of numbers, or unnecessary words to make it easy for your visitors to remember and find your website. Remember: A great domain name is one that your visitors can type correctly on their first try.