you can only trade with yourself with the shared bank and you can only trade treasure cards with other people. but if you want to give your other wizards some item that's better for them all you have to do is put something in it
Items put in the shared bank can only be used by the wizards in your account. Let's say for example that you have 2 wizards on one account. One is fire and one is storm. Your fire wizard gets a storm item in battle. You go to your bank and put the storm item in the shared bank section. Then switch to your storm wizard, go to the bank, go under shared bank, and put the item in your storm wizards backpack.
The only items you are able to switch between friends is treasure cards.
