How do capacitors affect voltage?

Hint: A capacitor is an electrical device, which can store electrical energy, and later discharge them at any given instant. This property of the capacitor is called capacitance of the capacitor. To understand the effect of voltages on a capacitor, let us look at the functioning of the capacitor, as discussed below.
Formula used:
$Q=CV$

Complete answer:
A capacitor is made up of two metal plates which are separated by a small distance. The distance between the plates is filled by an insulating material called the dielectric constant. When these plates are connected to a potential difference, one side of the plates gets charged while the other side gets induced by the opposite charge.
We know that the potential difference and the charges on the plates produce an electric field between the two plates, this is called the charging of the capacitor.
Then, if C is the capacitance of the capacitor and Q is the current due to the potential difference V, then we have
$Q=CV$
Later when the potential difference is removed, and the capacitor is connected to another circuit, it now acts as a battery, and discharges the electric field present in it, this is called discharging.
Then, clearly we can say that in any given capacitor, the charge due to the potential difference is directly related, which means that increase in voltage, increases the current in the capacitor.

Note:
Capacitance of a capacitor depends on the dielectric material present in between the plates, the distance between the plates, and the area of the plates. The charges on the capacitor is due to both charge transfer due to potential and also due to induction of charges.