Definition 1 of Coulomb

The SI unit of electric charge is coulomb which is denoted by the letter C.

One coulomb is that quantity of electric charge which exerts a force of $9 \times 10^9$ Newtons, on an equal charge placed at a distance of 1 metre from it.

Definition 2 of Coulomb

Charge of 1 electron is $1.6 \times 10^{-19}$ C. Therefore 1 C of charge is equal to the charge of $6.25 \times 10^{18}$ electrons.

Electric Potential

Electric potential is defined as the work done in bringing a unit positive charge from infinity to that point in the electric field. Electric potential is a scalar quantity and is denoted by the letter V. Electric potential is measured in volts (V).

Note that Potential is always measured with respect to work done. This is something like a hidden capability that a student earns by doing work. This work has two components - Force and Distance. Something like, just sincere studies on one day is not enough to crack IISc. Bikas needs to study hard every day for the entire 3 years to be able to crack IISc. So, unlike charge, potential is not just Force. Rather it is $Force \times Distance = Work$