Electricity and magnetism are related to the existence and motion of electric charges.
Law of conservation of charge: the amount of charge in a region cannot change except by charges flowing across the boundary of the region.
A flow of charges is called current.
Both insulators and conductors can be charged. When charges are placed on conductors, they repel each other and spread out to minimize electrostatic potential energy.
The electric field of a point charge is . points from the point charge to the point of interest, and is placed at the point of interest. Electric fields exist regardless of the presence of a second charge.