The Now Playing app lets you control audio playback on Apple Watch, iPhone, and other devices.
You can open Now Playing in the following ways:
Go to the Now Playing app on your Apple Watch.
If more than one device is available to play audio—an Apple Watch, iPhone, and HomePod for example—the device’s icon appears in the top-right corner.
Tap to see a list of devices, scroll to iPhone, then tap it.
Open an audio app such as Audiobooks, Music, or Podcasts, then choose audio to play.
Audio will play through your iPhone’s speaker or an audio device paired with it.
While controlling audio on an AirPlay device such as HomePod, you can switch to or add additional AirPlay devices. For example, if you’re listening to HomePod mini in your living room, you can add the HomePod speakers in the kitchen and bedroom.
Go to the Now Playing app Choose an audio destination on Apple Watch