In previous version of xcode 7, we can run our app on real device by adding apple id to xcode account and then selecting team.
But as now release of xcode 8 beta 2,
You need to register a device.
To do so:
Later you can remove the USB cable to test your app on the device. If you would like to copy the changes to your device, connect the device again and run.
You need to connect a device to Xcode and allow it to register it on your personal team. This will allow Xcode to create profiles for you (profiles cannot be created unless there is at least one device registered).