A domain name registration is simply reserving your website's name for a specified period of time. The two parties involved with a domain registration are generally the user who is registering the domain and the domain registrar. The domain registrant is the user who actually registers the domain name and the domain registrar is the company who helps that user with their domain registration.
Classic domain extensions work for both options, as well as country specific extensions to build up local relevance. nTLD domain names such as .design, .business, or the eye-catching .nyc are good, .business especially in the case of a website builder package. There's often confusion surrounding the nTLDs, and it's good to know that the TLDs that imply a geographical reference are classified as generic top level domains by Google. For those who opt for website builder packages, it may be worth registering more than one domain extension, especially the classic extensions such as .com, as many users will remember this one better than the nTLDs – if you own the .com version but prefer the nTLD, you can always set up domain forwarding to avoid competition from other websites.
Getting a domain name involves registering the name you want with an organisation called ICANN through a domain name registrar. For example, if you choose a name like "example.com", you will have to go to a registrar, pay a registration fee that costs around US$10 to US$35 for that name. That will give you the right to the name for a year, and you will have to renew it annually for (usually) the same amount per annum.

The way that competition is supposed to work between registries, is that lots of companies go to ICANN and say “We think we can reliably manage .com, and we think it would cost us [$5] per domain.” ICANN reviews these bids and awards the .com contract, which lasts for a fixed period of time, to whomever they deem best-suited to the job. In this time, other companies can think of ways to manage .com better/cheaper, and try and win the next contract. This, in theory, would provide an incentive for registries to innovate, a big part of which would be in lowering costs.

Domain Privacy prevents these spammers from collecting your personal info. DreamHost’s complementary (yes it’s free for the life of your domain) Domain Privacy service works by masksing your personal information in the WHOIS database with DreamHost’s corporate information, so you’re protected from unscrupulous marketers, spammers, robo-callers, junk mailers, and stalkers.
In order to register any domain, you must provide certain personal information that you may not wish to be publically searchable in the Whois database. Signing up for WhoisGuard is a great way to keep your registration data private. WhoisGuard acts as a "shield" for your searchable information, displaying the address, phone number, and email of the domain registrar (Namecheap, e.g.) instead of your own. Keep in mind that WhoisGuard is an optional security add-on that must be renewed separately when you renew your domain.