THANK YOU for actually explaining this correctly! SO many people make these videos and completely FAIL to explain it and/or their circuit doesn't work. Thank you for solving my frustrations!
In the case of through-hole capacitors, the capacitance value, as well as the maximum rated voltage is printed on the enclosure. A capacitor that has “4.7μF 25V“ printed on it has a nominal capacitance value of 4.7μF and a "maximum voltage" rating of 25 volts, which is never to be exceeded. So if you are not exceeding 16v then either one of them will work for you.