The "charge" can be positive i.e carried by proton and negative i.e carried by electron, known as the physical property of matter, which experience force when placed in an electromagnetic field.
The basic characteristic of charge is that the like charges repel each other while opposite charge attract each other. The SI unit of charge is coulomb (C) and symbol to represent charge on any entity is "e". When the number of proton i.e "e+" is equals to number of electron i.e "e-" than a body is said to be neutral.