Depending on the software version of the headunit it can be that full screen won't work (you'll see on the right side a message that your phone is connected via car play). Full screen can be activated via BimmerCode and you need “NBTevo_X“ and “NBTevo_Y“
You can easily check for yourself which software version is currently installed in your vehicle. To do this, navigate to the version info in the iDrive system in your vehicle (Navigation > Settings > Position and version > Version information). If you can see “NBTevo_X“ or “NBTevo_Y“ here, then full screen mode will work. If you see “NBTevo_N“, “NBTev

“, “NBTevo_P“, “NBTevo_Q“, “NBTevo_R“, “NBTevo_S“, “NBTevo_U“, “NBTEvo_V“ or “NBTEvo_W“ instead, then full screen mode can not be enabled with BimmerCode unfortunately, as far as I know though you can update your system at a BMW dealer.
Since my i3 is running on _P I will make a visit to our local BMW dealer and see if they can perform an update (and how much they charge for it

)