Put simply, a domain name is the mechanism that helps identify and locate computers and resources connected to the Internet and while there are free domain names, you usually have to purchase them through domain registrars.
One of the most essential features of a domain name is that it is unique, which is to say that no two computers (or servers) on the Internet can have the same domain name.
If you want a presence on the Internet you need to register a domain name that will then serve as your unique online name. Visitors will interact with you using this domain name either via your website or via email.
CentralNic Group Plc (LON:CNIC) provides registry services, distribution, and strategic consultancy for new TLDs, ccTLDs and SLDs.