you’re free to only send heartbeats to Apple Watch and iOS machine owners.
This feature isn’t supported by Android devices.
TapMessageson the home screen of your Apple Watch.

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Tap the conversation or person you wish to send the heartbeat to, and then tap theDigital Touchicon.
Tap and hold two fingers to the screen until the heart appears and starts to beat.
Take your fingers off the screen to instantly send the message.

Caiaimage / Trevor Adeline / Getty Images
Want to send a broken heart instead?
Drag your fingers down the screen before releasing them.
OpenMessagesandtap the conversation or person you wish to send the heartbeat to.

Tap in the message field, and then select theDigital Touchicon.
Tap and hold two fingers to the canvas displayed at the bottom of the screen.
Release your fingers to send the message.
Your heartbeat is on its way.