Capacitance is a measure of the (electrical) 'strength' of the electric field between the plates.

The field strength decreases with increasing distance of separation between the plates.

Capacitance is also a measure of the total charge stored on the plates for a given charge density (charge per unit area).

So the greater the area, the greater the stored charge.

The voltage is another measure of the field stength and the three quantities , voltage (V) , charge(Q) and capacitance (C) are connected by the equation

Q = CV

So knowing any two of these quantities determines the third ( a bit like Ohms law).