The force exerted on a charge $q$ in a uniform electric field $E$ is
The work done on moving the charge a distance $d$ in the field is
The potential difference, or voltage, between two points is defined as the work per unit charge to move the charge between the two points, or
So your formula is for work, not voltage.
To answer your follow up comment:
Why do a need this idea of work per charge, we didn't have that when we explaind gravity, right?
In classical mechanics, the "gravitational potential" at a location is equal to the work per unit mass that would be done by the force of gravity if an object were moved from a specific location to a fixed reference location. It is therefore analogous to the "electrical potential" with mass fulfilling the same role as charge.
On the other hand, "Electrical potential energy" = $qEd$ is analogous to "gravitational potential energy" = $mgh$.
Or to put it another way, electrical potential is not the same thing as electrical potential energy and gravitational potential is not the same thing as gravitational potential energy.
Hope this helps.