When you register a domain name licence, you get the right to use that name. Web hosting is how you can use that name as an address for your website or email. In most cases, unless you intend to host your website and email yourself, you will need both a domain name and web hosting.
Your domain name is what people will type in when they want to visit your website or send you email. However, you will need a computer to store or 'host' your website or email. This computer, usually referred to as a web server, is the place where the data (files) for your website is kept.
Web Hosting and Email Hosting are services that we provide that give you access to all the technical infrastructure needed to run a website or have email on your domain, without any need for technical expertise or expensive hardware purchases. You don't need to buy a server, as we become the "web server" part of the equation, which provides you with a place to upload your website files.