Can I use iPhone and iPad for one account? November 25, 2020 05:51 Updated You can use both iPhone and iPad for one account. Related articles Can I use more than one device with the same OS for one account? 5.Useful Functions Failed to communicate with server. (CE001/CE008) This user ID is already registered by other device ID. Please contact administrator. (L009) Can I use more than one device with different OS for one account?