Ah right, so in moon/and ultra like qr codes in animal crossing; there's qr codes for all pokemon, even shinies and it adds to your pokedex. In one day if you collect 10 qr codes, you can then scan (depends where you in the island plus what route) you can scan in several pokemon. One example is Axew. Its for an hour and i think after an hour or two you can scan again. Each day has different pokemon for each island.