No answer is universally correct but here’s two use-cases so you can pick which is more appropriate for you.
If you’re interested in technical details, the best really is to read relevant standards. However, it’s relatively easy to give you a good idea of what they are.
Quantum cryptography is still some years away from being anything but an interesting research area. But if you want to see what it is to suddenly have all your keys broken, look the ROCA vulnerability.