A MOSFET is a type of transistor we can use as a digital switch. The name stands for Metal Oxide Silicon Field Effect Transistor. The first MOSFET was made in 1959 by Mohamed M. Atalla & Dawon Kahng.

• Easy to manufacture in volume
• Easy to change its size
• It is the basic building block of modern electronics

They are the most manufactured object worldwide: 1.3×10^22 of them have been made between 1960 and 2018 - Wikipedia

Image is from components101

Operation

You can see the gate and body connections as the 2 sides of a capacitor. When an electric field is applied by charging the gate, the electro-chemistry of the channel region will change and allow current to flow between the source and the drain.