Share screens with another person
When you’re having a conversation with someone in Messages, you can share your screen with them, or they can share theirs with you. It’s a great way to work together on a project or help a friend do something on their computer.
When you start sharing screens with someone, an audio call begins automatically, so you can talk as you work.
Note: You can only share screens using iMessage on a Mac.
Share a screen
Select the person you want to share with in the Messages sidebar, then click Details.
If the person isn’t in the sidebar, send them a message first.
Click the Screen Share button
, then do one of the following.Share your screen: Choose “Invite to share my screen.”
View your friend’s screen: Choose “Ask to share screen.”
When the screen-sharing request is accepted, the Screen Sharing app opens. For information about using the Screen Sharing app, see Screen sharing overview.
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 your friend’s screen: Choose Screen Sharing > Quit, or click the red close button in the screen-sharing window.
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.
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.
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 your friend to share their screen. After they accept, click
in the menu bar, then choose “Allow [name] to control my screen” so there’s a checkmark 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 checkmark.
If you donʼt give someone screen control, they can still click to highlight areas on your screen.
If you can’t share a screen
If the Screen 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. (For more information, see Create a contact card.)
Tip: You can also share screens without using the Messages app, using macOS screen sharing. For more information, see Set up and use screen sharing.