I understand you're looking for QR codes related to Pokémon randomizers for the 3DS.
Here’s what you need to know:
You cannot scan a randomizer QR code with a stock, unmodified Nintendo 3DS. The stock camera app only reads friend codes and web links. To use these QR codes, you must have Custom Firmware (CFW) installed.
Your Checklist:
.cia version.Warning: Modifying your 3DS is a reversible process, but it requires following a guide exactly. Do not watch outdated YouTube videos. Visit 3ds.hacks.guide for the only up-to-date installation method.
If a friend sent you a QR code for a "Kaizo" randomized run of Alpha Sapphire:
Note: The randomization is permanently embedded into your save file. If you want to revert to vanilla, you must either restore a backup save (PKSM automatically creates one) or scan a "blank" QR code that disables all randomizations.
TL;DR: Using QR codes to inject randomized Pokémon games (like Omega Ruby, Alpha Sapphire, X/Y, or Sun/Moon) is a fascinating loophole, but it is generally less stable and more tedious than traditional randomization methods. It is best reserved for players who cannot use a computer or homebrew their 3DS.