No, that is not possible. For insurance reasons every driver must have the minimum age required to drive the car.
Please note age limitation is different depending on the car and the location where the rental takes place. The minimum age will be displayed during the booking process.
The car is locked/unlocked with a virtual key that is downloaded on the main driver's phone.
Just like a real key, this virtual key can be used by only one person at a time.
Additional drivers can of course request the virtual key to be transferred to their phone at any time.
Please note that, while it is not necessary to have internet to connect to the car, it is required to request the transfer of the virtual key to your phone.