Two charged particles with the same charge such as protons repel each other and move away from each other.Two charged particles with opposite charges such a proton and an electron attract each other and move towards each other.
The electromagnetic force is the force between two charged objects due to the exchange of virtual photons
They are 'virtual' because they cannot be detected directly.When two objects interact they exert equal and opposite forces on each other.Momentum is transferred between the two objects that interact. Momentum = mass × velocity.