How do generators in traditional cars supply power to the outside world?

The battery supplies power to the rotor and generates a magnetic field. (Needless to explain, the energized coil generates a magnetic field.)

When the rotor rotates, the magnetic field also rotates, and the stator winding cuts the magnetic field lines to generate three-phase alternating current.

Alternating current changes from alternating current to direct current through a rectifier bridge.

Then the voltage is maintained at a certain level by a voltage regulator.

Conclusion: The automobile alternator outputs direct current with fixed voltage.