https://www.techradar.com/news/googles-new-wear-os-phone-app-brings-quick-replies-to-smartwatches

Google has released a new Wear OS Phone app for Android Wear smartwatches that allows you to send messages and make calls in a more streamlined way. 

Wear OS Phone has a feature called Quick Replies that allows you to reply to a call using SMS, much like you can currently do on your Android phone.