In order to transfer money between your own cards registered in the app, all you have to do is log in (of course) and select the "Between cards" option. Choose the card you want to transfer from and the card you want to transfer to. Easy-peasy, right? 😉 Keep in mind though that transfers between your own cards in the same currency are only possible if the card accounts are different. Transaction authorization is done by entering the PIN set in the app or biometrics.