The exchange is powered by a credit or debit card that you'll need to add to your account before sending/receiving cash for the first time. Once a card is added, you'll create a PIN that will be entered each time you want to send money. And as you might expect, iPhone and iPad users can enable Touch ID to handle the added security. If you're worried about keeping your banking details safe, Facebook says its years of experience handling loads of daily payments for games and ads should help you rest easy. What's more, the connection between your device and Facebook's servers is encrypted, as are any financial details that you store in the app. The feature is only available in the US right now, and it'll be accessible on the desktop Android and iOS devices.