Facebook Messenger to launch mobile payments
To make a payment via Messenger, users will just need to tap the new dollar sign button, enter the amount, and then select Pay. To send or receive cash, it's necessary to add a Visa or MasterCard debit card issued by a US bank to your Facebook account.
It's not clear when (or if) the service will roll out internationally - presumably, after a successful trial period, it will be available everywhere.
Source:Facebook Messenger to add "send money" feature