http://www.techradar.com/news/apple-watch-now-lets-you-send-money-to-your-friends-with-apple-pay-cash

Image credit: Apple

Originally a questionable device, the Apple Watch continues to come into its own thanks to a steady rollout of appealing features for watchOS. The latest of these is Apple Pay Cash, which now lets Apple Watch users in the US send money to any other iOS users directly through the smartwatch's interface.

The only real requirement is that both sender and receiver have iPhones running iOS 11.2 and that you have a debit or credit card linked to your Apple Pay account.