Each iPhone lock requires a different iPhone Unlocking Method.
Benefits of an Unlocked iPhone
A Locked iPhone has many limitations and in most cases, you will not be able to use it at all. By performing an iPhone Unlock, you will be able to Unlock your iPhone and start using it with any Carrier you want. Also, Unlocked iPhones have a much higher price than a Locked one.
How to Unlock an iPhone
Currently, there are 3 methods that can remove the SIM-Lock from an iPhone: