Apple Pay Cash, Apple's peer-to-peer payments service, is now available for US-based developers and public beta testers, following the release of a second iOS 11.2 public beta.
The Venmo-like service, which was announced earlier this year, allows users to send and receive cash inside the Messages app on iPhones. To quote Apple: “Now you can use Apple Pay to pay and get paid right in Messages, or by asking Siri. There’s no app to download, and you can use the cards you already have in Wallet. Send money for books to your son in college. Split a bill. Pay a babysitter. Send and receive from across the table — or across the country. Instantly."
Further details here.