Messages is the text-messaging software included with your Mac. Use it to send messages from iMessage or other messaging services.
Set up iMessage
iMessage is the Apple messaging service you get automatically with your Apple ID. If it's not already set up, you're asked to sign in when you first open the Messages app. Sign in with same Apple ID that you use with Messages on your iPhone and other devices.
Add a Tapback to a message
macOS Sierra introduces Tapback to the Mac. A Tapback is a quick response that expresses what you think about a message, such as that you like it or think it's funny.
Send text messages to anyone from your Mac
If you have an iPhone with an active cellular plan, you can set up Messages to send and receive SMS and MMS messages from your Mac. Such messages don't require the recipient to be using iMessage or an Apple device