Capacitance and Voltage of Capacitors
1) The voltage of a capacitor is a potential difference that the two plates or sides of the capacitor develop when voltage is applied. This is the actual voltage.

2) The capacitor voltage rating is the maximum voltage practically allowed by the manufacturer for that part.

So, a 10uF 16V capacitor can be charged with a voltage up to 16V without damaging it, although getting close to 16V is bad engineering practice since its close to the limit of the part. The higher voltage could cause a dielectric breakdown which basically destroys the capacitor.

Please note that ceramic capacitors lose their capacitance when the voltage applied to the capacitor is close to the voltage rating. This can mean a loss of 50% or more of the capacitance. Therefore, you always want to have plenty of margin.