I believe its similar to PayNow Singapore, UPI India, PromptPay Thailand etc where you register your phone number with your bank app, you can send money to those mobile who are on the same network using your bank app, or use your bank's app to scan a QR when making payment to a vendor. The QR code is actually the vendor's number. There are now cross border link, for example I can send money to someone in India using just his mobile number on UPI.