The purpose of pressing the clutch on a motorcycle when coming to a stop is to disengage the engine from the transmission, which allows the rider to control the bike's speed and come to a complete stop without stalling the engine. When you pull the clutch lever on a motorcycle, you separate the clutch plates, which interrupts the power transfer from the engine to the wheels.
By disengaging the clutch, you effectively disconnect the engine's power from the rear wheel, allowing you to coast or roll freely without the engine's resistance. This enables you to modulate your speed and gradually decelerate as you approach a stop, maintaining better control over the bike. It also prevents the engine from stalling when the bike slows down or comes to a halt.
When you're ready to accelerate again, you can release the clutch lever gradually while simultaneously applying throttle, which re-engages the clutch plates and transfers power from the engine to the wheels, allowing you to accelerate smoothly.