Tesla has released a few more photos of the Model 3, this time centered around the keycard and phone app for door entry, and starting the car.
Tesla Model 3 - Keycard Door Entry
The base way to open the car and drive seems to focus on an app for iOs and Android, that enables keyless entry, provided one configures the Bluetooth connection.
Once the connection is set, the owner simply approaches the vehicle to unlock it and drive. That's an entirely different approach than today in the Model S or Model X, which uses a key fob as the default mode for keyless entry.
The second option for operation and entry for the Model 3 is to use a factory provided keycard, embed with a NFC chip that needs to be swipe/tapped on the driver's door B pillar, below the Autopilot camera.
Unlike a key fob, the keycard is unable to open the doors or trunk via buttons, but is possible to put in one's wallet (as a reserve option, if something were to happen to your phone).
Tesla Model 3 - Interior Keycard and Phone Dock