You'll then be presented with all the Pokémon that reside in your PC boxes within the game – not your party though – allowing you to transfer any you wish to move to Sun and Moon. Pokémon Bank currently works with Pokémon X, Pokémon Y, Pokémon Alpha Sapphire and Pokémon Omega Ruby, and from January it'll also be compatible with Pokémon Sun and Moon along with the digital re-releases of Pokémon Red, Pokémon Blue and Pokémon Yellow. However, to actually use Pokémon Bank requires an annual fee. Otherwise, just head to the Nintendo eShop and download it manually for free. If you purchase any of the 3DS-compatible Pokémon games – Pokémon X, Pokémon Y, Pokémon Alpha Sapphire and Pokémon Omega Ruby – it should be automatically installed onto your 3DS/2DS/3DS XL. However, that does mean that all the other Pokémon games, even the Virtual Console re-releases of Red, Blue and Yellow on the 3DS, will be left out of the Pokédex. When that compatibility does arrive, Pokémon Bank will then get an amazing new addition – a new Pokédex that tracks all the Pokémon you've caught across every 3DS game in the series. You put all the critters you want to take forward to Pokémon Sun and Moon in there whenever you're ready and then they'll be good to go come January.

It allows you to deposit, store and then transfer your Pokémon from one Pokémon game to another, basically like a master version of the classic PC from the Pokémon games themselves.

Pokémon Bank is an application for the 3DS family that originally launched with Pokémon X and Y.

How to get pokemon bank on another 3ds