For the most part, you can pick whichever TLD you prefer, though a few have restrictions -- you can't buy a .edu domain unless you run an accredited post-secondary school. Many, but not all, country-specific domains (.us, .uk, .jp) are restricted to citizens of the country in question. Unrestricted country domains are often used for "domain hacks," where the extension becomes part of the title, such as YouTube's alternate address, "youtu.be."
With over 25 million .com domains registered with Google alone, this top-level domain is by far the most popular choice worldwide. According to the domain marketplace Sedo, the average sales price for a .com domain name during the second quarter of 2015 was 4,701 dollars. The most expensive publicly traded domain names have been known to fetch eight-figures. But don’t quit your day job just yet: such sales are the exception rather than the rule.
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.
The character set allowed in the Domain Name System is based on ASCII and does not allow the representation of names and words of many languages in their native scripts or alphabets. ICANN approved the Internationalized domain name (IDNA) system, which maps Unicode strings used in application user interfaces into the valid DNS character set by an encoding called Punycode. For example, københavn.eu is mapped to xn--kbenhavn-54a.eu. Many registries have adopted IDNA.
It's good to decide early on if you want to have a brand domain or a keyword domain. The benefit of a brand domain is that your domain will most likely be considered as trustworthy, and immediately shows visitors that it's linked to your business or personal blog. A keyword domain, on the other hand, has the advantage that it will be better optimized for search engines, and therefore will get higher search results. In recent years, however, the drastic improvement in search results thanks to a keyword domain has begun to decrease.
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).
Sedo is where I bought my domain - over Escrow - and is a global marketplace to buy, sell, and park domain names. They've over 18 million domain names for sale, but the big part is that they're a huge, well-respected company. This may not be important if you're spending $150 on a domain, but in a $15,000+ purchase - which happens in many cases - you will be potentially buying from a foreign entity, that you don't know, and many of them will suggest an escrow payment. This means you put the money in an account owned by a third party that will hold it and only pass it on once the domain has been transferred over into their name (which in this case is what Sedo does). This can be quite disconcerting - but Sedo is well-known and has done many, many deals - and the process is about as full of hand-holding as handing tens or hundreds of thousands of dollars for a domain name can be.
A domain name can be used for a variety of purposes. Many people who are not ready for a website simply register the domain name of their choice to ensure it doesn’t get snatched up by anyone else. They may use it to create a professionally branded email address, or as a Web address that can point customers to an alternate online presence, such as their social media page, if they don’t yet have a website.
Domain names can be used in a number of ways. Direct visitors to your website’s home page or use complementary domains to send them to specific areas of your website ( e.g. yourcompany.jobs for a careers page). Or, forward a custom domain to an existing social media account, like your Twitter profile or Periscope channel. With a domain name you can even set up custom email addresses like email@example.com, which can be used to conduct business or communicate with your followers. More.