The Poké Transporter (Japanese: ポケムーバー Poké Mover) is an extension released for the Pokémon Bank app through the Nintendo eShop on the Nintendo 3DS. While the Pokémon Bank has an annual fee for the service, Poké Transporter is free and can be downloaded inside of the Pokémon Bank application.
The Poké Transporter allows people to transfer Pokémon from any of the Generation V games over to the Pokémon Bank. To do such, you must insert the Generation V game into the 3DS and once there, you can transfer the Pokémon of your choosing. Once a Pokémon is in the bank, it can be transferred over to one of the Generation VI games.