What is the working principle of a touch pen (capacitive pen)?

What is the working principle of a capacitive pen and how is its operation achieved?
Capacitor pens have conductivity and are used to replace our fingers for operation, but they are more flexible, agile, and convenient than our phones. The capacitive touch screen works by utilizing the current sensing of the human body. It is a four layer composite glass screen, and the inner and outer layers of the glass screen are coated with a layer of coated conductive glass. When the phone comes into contact with coated conductive glass, a coupling capacitor is formed between the human electric field and the surface of the touch screen. A capacitor is equivalent to a direct conductor, and a finger draws a small amount of current from the contact point. The controller calculates the position of the touch points by accurately calculating the current.
In general, a capacitive pen is a device that uses conductive materials to simulate a human-machine conversation with fingers.