The clicking sound you hear when turning off a motorcycle is typically caused by the solenoid or relay engaging and disengaging.
The solenoid or relay is an electrical component that controls the flow of electricity to various parts of the motorcycle's electrical system. When you turn off the motorcycle, the ignition switch interrupts the power supply to the engine and other electrical components. As a result, the solenoid or relay receives a signal to disconnect the power.
The clicking sound is produced when the solenoid or relay rapidly switches on and off to break the electrical connection. It is a normal part of the electrical system's operation and indicates that the power supply is being cut off.
Additionally, some motorcycles may have additional systems that click when turning off, such as the fuel pump or other mechanical components. These clicks can also be normal and are part of the system's shutdown process.
If you notice any unusual or persistent clicking sounds when turning off your motorcycle, especially accompanied by other electrical issues or starting problems, it would be advisable to have it inspected by a qualified mechanic to ensure there are no underlying issues with the electrical system.