Can Apple install my macOS?
I don't install MACOs, can apple install online on this device(sn: W8***66E)?
[Edited by Moderator]
No, Apple cannot. You can go to an Apple store and ask if they will do it there. Otherwise, you can easily install it yourself.
However, you may want to explain exactly what it is that you need to do or how you got to that point so we can help you better.