Web hosting (sometimes referred to as 'web space') is a service which allows you to upload your own files and site to a shared server in our data centre. Once uploaded, your website can be seen by anyone who is connected to the Internet. Any 123-reg customer can attach hosting to the domain name packages in their account.
Please note: If you have chosen to use the InstantSite system then you don't need additional hosting, as InstantSite comes with its own web space.