Hello @monkus, I would be glad to assist you. What you need is a signature card. You can request one on usaa.com. You will print it out, both you and the person your adding sign it and upload it back to us. Here are the instructions. I hope this helps. ~Suzy (=
From My USAA:
Select the deposit account.
Select the Account Details tab.
From the Account Holders section, select Add An Account Holder.