Locked MetroPCS Android phones released after 2,015, are not unlocked using unlock codes. However, this doesn’t mean it’s unlocked. Even though your phone does not ask for an unlock code, it still needs to be unlocked; this is done through MetroPCS’s Device Unlock App.
This application should be pre-installed in your phone. You can find it by pressing on the MetroPCS icon on your apps. Our team at UnlockRiver unlocks it remotely, and when unlocked, you will receive an email an have to follow some simple steps.
(This video shows the procedure for a phone from T-Mobile but the process it’s identical to MetroPCS)