As well as a domain name (eg example.com) your website needs to reside on a web server somewhere on the internet. This is essentially a computer housed in a datacentre that is attached to the internet and capable of being accessed using a web browser. The webserver consists of specialist software to manage and server your website, including a specialist operating system, security software, the webserver management software and a database which contains most of your website content.
Your webserver is accessed via an IP address which usually consists of four 3 digit numbers separated by fullstops (eg 192.168.0.1). Your domain name is translated to the webserver IP Address using the Domain Name Service (DNS). Think of your domain name as a PO Box and your webserver as your website’s physical address.