What is actually a domain?
A domain can represent your name or project on the Internet and make it accessible worldwide. You can use a domain to make a website accessible online, for example, you can also redirect a domain to a Game or TeamSpeak 3 server and have it then also reach online with an easy to remember name.
A subdomain is a subdomain which you can create for your existing domain at any time free of charge. This is done via the DNS settings, a subdomain can look like this for example: server.fivem-server.com Here server is your subdomain and fivem-server.de is the name of the actual domain. A subdomain usually redirects to a different address than the actual domain, for example, you can make your website reachable with fivem-server.de while you can make your website reachable with server.fivem-server.de to your FiveM or another game server. You will find the DNS settings in the menu on the left.
Domain's and IP addresses
In contrast to an IP address you have to rent a domain individually, this is NOT automatically included with a game server, root server, vServer or voice server. A domain is already different in appearance from an IP address. While an IP address consists of numbers, for example 18.104.22.168, a domain has a correct name and a corresponding domain ending, for example fivem.net. Here fivem would be the name of the domain and .net the domain ending. Besides .net there are of course many other domain extensions like .com or .de.