Use Messages in iCloud on Mac
With Messages in iCloud, all the messages you send, receive, or delete are updated on all your devices automatically. Keeping your messages in iCloud also helps you save space on your Mac.
To use Messages in iCloud, you need macOS 10.13.5 or later, iOS 11.4 or later, or iPadOS 13 or later. You need to be signed in to iMessage using the same Apple ID on every device where you want to use iMessage.
Turn on Messages in iCloud
On your Mac, choose Apple menu
Sign in: Click Sign In, then sign in with your Apple ID. Use the same Apple ID you use to sign in to Messages.
Verify your Apple ID: Click Apple ID, then make sure you’re signed in to iCloud with the same Apple ID you use to sign in to Messages.
Select Password & Security in the sidebar, then make sure that two-factor authentication is turned on. See Set up your Apple ID password and security information.
In the Messages app
on your Mac, choose Messages > Preferences, then click iMessage.In the Settings pane, select “Enable Messages in iCloud.”
The messages from your other devices that use the same Apple ID appear on your Mac.
Important: Depending on how many messages you have, it may take some time for all of them to appear. You can send and receive messages during that time.
To make sure you’re seeing the latest messages in iCloud on your Mac, choose Messages > Preferences, click iMessage, then click Sync Now in the Settings pane.
Turn off Messages in iCloud
You can turn off Messages in iCloud just for this Mac or for all devices where you use it.
In the Messages app
on your Mac, choose Messages > Preferences, then click iMessage.In the Settings pane, deselect “Enable Messages in iCloud.”
Choose one of the following:
Disable All: Turns off Messages in iCloud for all your devices. Messages are longer stored in iCloud and are instead stored on each device.
Disable This Device: Turns off Messages in iCloud for your Mac only. Messages on your Mac are no longer stored in iCloud; on any other device where Messages in iCloud is turned on, messages continue to be stored in iCloud.