Which Apple ID is used for Apple Music—iCloud or iTunes? I have different Apple IDs for iCloud (backups, iCloud Drive, Keychain Sync...) and iTunes (purchasing media—music and movies.) They are in different countries.

Which Apple ID is used if I sign up for Apple Music?

Is it even possible to be logged in with different iCloud and iTunes IDs and use Apple Music?
Your iTunes Apple ID is used. I also use two Apple IDs and the one logged in to iTunes &amp; App Store in Settings is the one which was used.