For more details, see the Libra.org site and this David Marcus thread
"We aspire to make it easy for everyone to send and receive money just like you use our apps to instantly share messages and photos. To enable this, Facebook is also launching an independent subsidiary called Calibra that will build services that let you send, spend and save Libra -- starting with a digital wallet that will be available in WhatsApp and Messenger and as a standalone app next year.
Calibra will be regulated like other payment service providers. Any information you share with Calibra will be kept separate from information you share on Facebook. From the beginning, Calibra will let you send Libra to almost anyone with a smartphone at low to no cost. Over time, we hope to offer more services for people and businesses -- like paying bills with the push of a button, buying coffee with the scan of a code, or riding local public transit without needing to carry cash or a metro pass."Mark Zuckerberg on Libra | Facebook