Each website (aka the computer where your website's files are stored) has its own IP address. It is a combination of numbers, for example, 234.591.45.381. Visually, this is perceived and remembered with difficulty, so they came up with a domain name. Domain name is the address of the website under which the IP address of the computer on which your website is stored is assigned. You can buy a domain on the websites of domain registrars. When you enter the website address «webdivision.pro» in the browser, the domain registrar looks at which IP address is assigned to the domain name webdivision.pro and redirects your request to this IP address. The domain, like the IP address, must be unique. Domain prices can be very different. It is possible to buy a domain name cheap, but domain renewals will be expensive. Therefore, it is better to choose from several registrars. Usually, a domain name can only be purchased for 1 year. You can check if the domain is busy here Check domain.
Domains contain levels and are structured in a hierarchical manner, that is, each level in the domain structure is created on the basis of the previous one. The levels consist of words, symbols and are separated by dots, and the set of levels makes up a fully qualified domain name, which is a unique address of the site. Let's consider an example xxx.super.webdivision.pro.:

• zero-level domain: this is a period at the end, usually it is not entered or displayed in the address bar, but it is in the address — this simplification is made for convenience;
• first level domain: .pro is the domain zone of the site;
• second level domain: webdivision is the name that is registered and purchased;
• domain of the third and more levels: super and xxx, respectively — usually these domains are created based on the name of the second level, they are also called subdomains. They do not require registration or payment.

It is very important to choose the correct domain for your website. The best domain names will be simple names that match the theme of the site. A simple name will be easier to remember and faster to find on the Internet, and the connection with the website's topic contributes to the promotion of the resource in the global search, since the search engine recognizes the meaning of the word and places it in the appropriate category in order from the greatest match to the user's request.