Do QR codes need to be registered?

No — there is no central QR code registry, and static QR codes require no registration, account or approval from anyone. The QR standard is open; you can generate a code right now, anonymously, and it will work forever. Anyone telling you a plain static code must be 'registered' (or renewed) is selling you something.

The only registration that genuinely exists is an account with a provider when you want dynamic features — because someone has to host the editable redirect and store your scan statistics, those codes are tied to your account with that service. That's a practical dependency, not an official requirement. So: static codes, zero registration, free forever; dynamic codes, an account with whichever service runs the redirects.