The charge stored in a capacitor can be calculated using the formula
Q = CV
Q is the charge on the capacitor
C is the capacitance of the capacitor
V is the voltage applied across the capacitor
When a voltage is applied across the parallel plate capacitor it will produce a positive charge on one of the plates of the capacitor and a negative charge is produced on the other plate. The charge produced on the capacitor is proportional to the voltage applied.