Charge is a property of all matter. There are two types of charge, positive and negative. Objects with the same type of charge repel each other, and objects with different types of charge attract each other.
Most objects have equal amounts of positive and negative charge. The charges cancel out, so the net charge on the object is zero and we say it is neutral. An object is only charged overall when it has more of one type of charge than the other.
You can see these forces for yourself. Two charged rods can be made to repel or attract each other. A charged rod can pick up small pieces of paper or bend a thin stream of water. A charged balloon sticks to a wall because the charges in the wall are pulled and pushed slightly, so the surface of the wall nearest the balloon has the opposite charge and the two attract.
