But here is the catch: randomizing a 3DS game isn't as simple as clicking a button on an emulator. For years, players had to dump their own cartridge files, run them through a PC randomizer, and then rebuild the CIA file.
Assuming you have found a verified randomizer QR code (more on where to find them below), here is the workflow: pokemon randomizer 3ds qr code verified
Download the community-verified Universal Pokémon Randomizer ZX on your Windows or Mac computer. This requires Java to run. But here is the catch: randomizing a 3DS
A Pokémon Randomizer for the Nintendo 3DS modifies certain game data so wild encounters, trainer parties, item loot, or Pokémon stats/abilities are randomized. Some communities share randomized Pokémon via QR codes so others can scan and receive the same randomized encounter or species. “QR code verified” in this context usually means the QR codes have been tested to work on actual 3DS hardware or reliable emulators and reproduce the intended randomized result. This requires Java to run
Which are you looking to randomize (e.g., Gen 6 or Gen 7)?