Sending data to your Watch app from your iPhone or from your iPhone to your Watch App after triggering some event is very simple, though the code can look a little complex at first.
let message = ["key":"value-to-send"] WCSession.default().sendMessage(message, replyHandler: { (replyMessage) in print("Got a reply from the phone: \(replyMessage)") if let returnedValues = replyMessage["returned-value"] as? NSArray { for val in returnedValues { // do something here with the data // Dispatch to Main Thread if affecting UI } } }, errorHandler: { (error) in print("Got an error sending to the phone: \(error)") })