With the ones I have used you just click around on the homepage selecting what you want on the server and then pay. Some sell second hand repurposed servers on auction that they will set up for you. A while later you get an SSH login on the server and that's it, your server is running somewhere in a basement/bunker/old mine and you can go visit it if you want but in general you can do everything remote. There is even stuff that can let you see the bootup in bios from remote (Called KVM I believe). Some help you set up backups on the server and help you with setting up programs on the server but then it starts to get expensive.
You can also just rent a space to place your own server but I haven't tried that.
You can also just rent a space to place your own server but I haven't tried that.