Voice control is a feature that enables you to accomplish various tasks on your smart phone e.g. you say “play” and your smart phone will start playing music, or you say “call Mommy” and your smart phone will dial a call to a number saved with name Mommy. This is feature of operating system and both IOS and Android have this feature.
If you are talking about unlocking screen of a smart phone than in Android it is possible with the help of third-party apps like Voice Lock Screen.
