There is a force between two charged objects. To decrease the magnitude of the force, you should

To decrease the magnitude of the force, move the objects farther from each other or reduce the charge on either of them.

Explanation:

The magnitude of the electric force between q1 and q2 is directly proportional to the magnitude of the charges and inversely proportional to the square of the distance between them. This equation is known as Coulomb’s Law.

F  ∝  1/D ^2

so the electrostatic force between two objects or particle is inversely proportional to the square of distance between the charges/objects.

If still you there is any confusion, feel free to ask