Send a message on Mac
Messages on Mac don’t have to be boring. After you set up your Mac, you can send messages to one person, a group of people or a business and include text, photos, animated effects and more. You can express yourself in all sorts of ways:
Tapbacks: See Use Tapbacks.
Photos and videos: See Send photos and videos.
Photos, scans and sketches (from an iPhone or iPad): See Insert files from iPhone or iPad.
Memoji stickers and images: See Create your Memoji and Use Memoji and #images.
Audio messages: See Send an audio message.
Message effects: See Use message effects.
In the Messages app
on your Mac, click the Compose button 
to start a new message (or use the Touch Bar).In the To field, type the name, email address or phone number of the person you want to send a message to. As you type, Messages suggests matching addresses from your Contacts app
or from people you’ve previously sent messages to.You can also click the Add button
to the right of the To field. Click a contact in the list, then click the email address or phone number.Note: If you’re restricted to sending and receiving messages with only certain people, an hourglass icon
Enter your message in the field at the bottom of the window. You can use typing suggestions, if available.
Siri: Say something like: “Message Mum that I’ll be late.” Learn how to ask Siri.
Press Return on your keyboard or click the Send button
to send the message.
If you want to reply inline to keep the conversation more organised, see Send an inline reply to a message. To forward a message, see Forward a message or attachment.
Tip: You can invite new friends to play multiplayer games by sending a message with your Game Center account. See Play games on your Mac.