Get your IMIE code first by typing *#06# on your keypad. Do this on either the main screen or in the dialing screen. You’ll need that IMEI shortly.
To unlock any GSM phone always first call your phone carrier’s customer service line while you have their SIM in the phone. It is the fastest and easiest way to unlock any phone. Most carriers will give you an unlock code once the phone is 3 to 6 months old. If you’ve had the phone for 2 years the unlock code should be free.