Share your screen using Messages on Mac
During a conversation in Messages, you can share your screen with the person you’re texting or they can share theirs with you. You can also allow someone to control your screen, or you can control theirs. It’s a great way to work together on a project or help someone do something on their computer.
Note: Another way to share your screen is to use SharePlay, which lets you share your screen in a FaceTime call. You can look at photos together, plan your next vacation and more. See Share your screen in FaceTime.
Share a screen
In the Messages app
on your Mac, do one of the following to choose who you want to share screens with:Select a conversation for the person.
Click the Info button
, click the Share button 
, then do one of the following:Share your screen: Choose Invite to Share My Screen.
View the other person’s screen: Choose Ask to Share Screen.
When the screen-sharing request is accepted, an audio call begins automatically (so you can talk while you work) and the Screen Sharing app
opens. For information about using the Screen Sharing app, see Share the screen of another Mac.To stop screen sharing, do one of the following:
If you’re sharing your screen: Click
in the menu bar, then choose End Screen Sharing. (If you’re not ready to stop yet, choose Pause Screen Sharing; choose it again to resume sharing.)If you’re viewing the other person’s screen: Choose Screen Sharing > Quit Screen Sharing.
Tip: Don’t want someone to send you screen-sharing invitations? When you receive an invitation from them, hold the pointer over the Decline button, click 
, then click Block User.
If you can’t share a screen
In the Messages app on your Mac, if the Share button is dimmed, try the following:
Make sure the person youʼre trying to share with is signed in to iCloud using the same Apple ID they used to sign in to Messages.
If they can’t sign in to iCloud and Messages using the same Apple ID, open your Contacts app
and make sure your contact card for the person includes both Apple IDs—the one they use to sign in to iCloud and the one they use in Messages. Then try sharing again. (See Create and manage contacts.)
Tip: You can also share screens without using the Messages app, using macOS screen sharing. See Turn Mac screen sharing on or off.
Allow someone to control your screen
When you share your screen with someone, you can also allow them to control your screen, which gives them complete access to your computer.
WARNING: Only allow people you trust to control your screen. They can do anything you can do on your computer – open apps, create or delete documents, copy files from your computer to theirs, and so on.
On your Mac, do one of the following:
If you received an invitation to share your screen: Click Accept in the invitation. A message asks if you want to let the other person control your screen or just observe it. Select “Control my screen”, then click Accept.
If you want to initiate screen sharing: Invite the other person to share their screen. After they accept, click
in the menu bar, then choose “Allow [name] to control my screen” so there’s a tick next to it.
To take back control of your screen – but still let the other person view it – click in the menu bar, then choose “Allow [name] to control my screen” to remove the tick.
If you donʼt give someone screen control, they can still click to highlight areas on your screen.