In iOS 13.4 Beta 1, CarKey's application interface appeared. In other words, in the future, users will be able to unlock their vehicles through their mobile devices. In Beta 2, foreign media MacRumors found a more detailed description of this feature, pointing out that this feature can also allow you to lend car key permissions to others.
The description indicates that CarKey can be transmitted in a conversation with other people, but cannot be transmitted in a group conversation. Those who receive the digital key through the Messages app will receive a message and learn that the key is ready for use in the vehicle:
[Vehicle Owner] invites you to use his [Vehicle Model] and gives you unlocking and driving authority. You can use your iPhone or Apple Watch to unlock / lock the car, start the engine and drive on the road.
Similar to CarPlay, since CarKey must be used through short-range wireless communication NFC, future car manufacturers may use this feature as an installation option for drivers.