Wear OS by Google uses four interaction types: notifications, watch faces, native apps, and
voice commands.
Notifications
Notifications provide ambient, contextual data. They often provide entry into your app.
Notifications can be expanded to offer lightweight experiences, such as replying to a message, opening a location on a map, or playing a song. Notification templates are available for instant messaging, music playback, and calendar events.

A notification in the notification stream
Watch faces
Watch faces can tell more than time; they can show relevant, timely data. By including a gadget called a complication, installed apps display useful data, such as an upcoming appointments.
With a single tap on the watch face’s complication, users can open an app. By long-pressing the watch face, users can change the look of the watch face itself, such as its color.

A watch face with data complications for an exercise and calendar app
Native apps
Developers can create branded, engaging experiences using native Android apps. These apps can take full advantage of the watch’s hardware capabilities to provide on-demand experiences.

The Wear OS by Google app launcher
Voice commands
Voice actions enable hands-free interactions with Android Wear. These actions tap into Google’s search services and can trigger specific actions on installed apps.

After the user has spoken the voice command, “Ok Google, show me my agenda,” the command appears as text on screen.