Send and receive messages
To listen to your message, select the notification.
Message notifications will appear at the top of the screen for a few seconds. If you dismiss a notification you can always go back to the Home screen to view it again.
You can tell Google to send a text message or read you one that you received through SMS or other compatible apps.
For Hangouts messages, you can receive and reply just like a text message.
Missed messages appear as notifications on your Home Screen. To listen to a missed message, select the notification.
- Say "OK Google" or select the microphone
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- Say “message,” "text," or "send a message to" and then a contact name or phone number. For example:
- “Message Cody White.”
- “Send a text to 555-555-5555.”
- "Message Cody White on Hangouts."
- "Message Cody White on Whatsapp."
- Android Auto will ask you to say your message.
- Android Auto will repeat your message and confirm if you’d like to send it. You can say "Send," "Change message," or "Cancel."
.Message notifications will appear at the top of the screen for a few seconds. If you dismiss a notification you can always go back to the Home screen to view it again.
To listen to your message, select the notification.
- Say "OK Google" or select the microphone
- Say “reply.” Your reply will automatically be for the last message you received.
- Say your reply.
- Android Auto will repeat your message and confirm if you’d like to send it. You can say "Send," "Change message," or "Cancel."
You'll also see an auto-reply card that says "Reply: I'm driving right now" on the Home screen. As soon as you select it Android Auto will send this message. You can modify your auto reply messages under Settings 
To stop seeing notifications for a specific message thread, select Mute. To turn notifications back on, simply select Unmute.