This feature is not yet available to everyone but there was another gradual rollout wave recently.
You will need to long-press on a message to see a popup window with reactions and additional options. You will be able to choose between 7 different reactions that are also Bitmojies themselves. In order to reply, you can simply swipe to the right on a message or choose this option from the same pop-up menu.
- 📲 Snapchat is a well-known social app with loads of AR lenses.
- 📲 Snapchat is available in Beta and you can opt-in as a tester via Google Play.