Electrostatic is study about the charge. In electrostatic we study about when charge at rest.
Charge:
Charge is important point for study about electrostatic.charge is a scaler quintity. And the unit of charge is in M. K. S is coulamb and in C. G. S is e. s. u (electro statics unit) and in magnetism it's unit is e. m. u (electo magnetic unit).
1c = 3 * 10 ^ 9 e.s.u
1e. m. u = 3 * 10 ^ 10 e .s . u = 10c
The formula of charge Q = ne
Here n is a integer no and e is charge of electron.