Transfer email domain to Apple icloud+

Hello, I need help transferring my email domain from my current provider, Westnet, to Apple iCloud+. I do have an Apple ID, but I'm not sure if I need assistance setting up the domain or accounts – it all depends if the transfer process is straightforward enough. If it's possible to just do the transfer and everything will be good, then I would just need the transfer done. If it's more complicated than that, then I'd like someone to provide assistance with the whole process to make sure it goes smoothly.