QR codes are being used by many games released on 3DS and they will also be featured in the newest game from the Pokémon series, Sun & Moon.
After scanning the QR code in most cases you will not receive the Pokémon instantly. It’s not that easy. But if you have never encountered it before then it will appear in your Pokédex and you will be able to easily check where can you catch it. It is also possible to generate QR codes to share with your friends. You can find the full list of QR codes below.