Static electricity is made when two surfaces are rubbed together. The rubbing leaves each surface charged, one positive and one negative. Static charge builds up readily on insulators, such as plastic, polythene and acetate. On a conductor such as a metal rod held in the hand, charge flows away, so it cannot build up. A conductor can only hold charge if it is insulated from earth, like the metal dome of a Van de Graaff generator.
The charge on an insulator stays where it is. As more charge builds up, it can become large enough to jump across a gap in the air as a spark. A Van de Graaff generator builds up a large charge on its dome until a spark leaps to a nearby earthed object.
Charged objects exert forces on one another without touching. If two charged balloons hang side by side on threads, they move apart or together, which is evidence of a force of repulsion or attraction acting at a distance.