What is the Shared Bank?
The Shared Bank:
Each character has access to a 9 slot 'Shared Bank', which is separate from your regular Bank, but accessed via the same terminal. The Shared Bank can be accessed by other characters on your account on the same server. The Shared Bank allows a player to move regular tradeable items, as well as Integrate on Equip, or account-bound items that have not already been attached/linked to a particular character. Items that are flagged as 'Cannot be Traded', or ones that flagged as Integrated can not be moved through the shared bank.
To access your Shared Bank, go to one of the bank locations in the Watchtower or Hall of Doom, and open up the Bank interface. PC players can click on the 'Shared Bank' tab, while PS4 players can use the R1 and L1 buttons to toggle between the Shared and regular Bank screens.