i'm making a personal promise to myself right now: i'm never typing an apple id email address or apple id password on a mac ever again.
you have to do it on iOS, because without identifying yourself to apple you can't even install free apps on your tablet or phone. i have throwaway, disposable email address apple IDs for that purpose there, which of course serve as permanent unique tracking identifiers. i'm not doing it on the mac, ever.
However, this excludes a synchronization of data between the devices.
@Th3G4m3r false:
there are end-to-end encrypted, private tools for synchronizing your data between devices that don't involve doxxing yourself to apple (or providing them with your keys or plaintext):