What are wire used for Electric Guiter?

Answer 1

depends on which kind of wire you mean , I'll go as simple as possible

to connect the electronics together so the electricity flows through:

the input jack to the pickup switch to the potentiometers (things under knobs) and through the capacitor of the tone potentiometer , the capacitor is a piece of plastic , oil or anything like that , some caps give you different sounds like Gibson used paper in oil style ones in the 1950s , yet today the cheapest to make are either ceramic or polyester.

getting back on topic though..

wires are also used inside pickups to make the humbuckers and single coils sound the way they should. 4 wire pickups have one wire per coil so when you use a special pot called a coiltap potentiometer and pull up on it , the humbucker will than sound like a single coil pickup.