When your iCloud account isn’t syncing on its own, you can manually sync your text messages. Here’s how:

On your Mac, open the Message app.

Under the Messages menu, choose Preferences.

Select the iMessage tab.

Ensure the Enable Messages in iCloud option is checked.

Press Sync Now.

This usually does the trick, and you should see your new texts appear in iMessage on your Mac. However, if this isn’t the case, work your way through the following options.

Check the Settings

Other than checking that your Mac and iPhone are signed in under the same Apple ID, you could verify that your iPhone is set to sync iMessages. Here’s how:

From your iPhone, launch the Settings app.

Select Messages and ensure the iMessage toggle switch is activated. If not, tap on it to turn it green. It might take a few seconds to activate.

Press Send & Receive.

If Use your Apple ID for iMessage displays, select it, then sign in using the Apple ID you used on the device you wish to sync with.

Beneath the You Can Receive iMessage to and Reply From heading, ensure the mobile number, Apple ID, and email addresses you use to text are enabled.

Beneath Start New Conversations From, tap your mobile number, unless you prefer to use one of your email addresses.

At the bottom of the screen, your Apple ID will display. This is the ID you’ll need to sign in with when accessing iMessage from your Mac.

For FaceTime:

Go to Settings, then select FaceTime.

Beneath You Can be Reached by FaceTime at, ensure your mobile number and Apple ID are enabled.

Ensure Your Mac and iPhone Are Updated

In order for iMessage to function as expected, it needs to be running on an up-to-date OS. Follow these steps to update your macOS and iOS on your iPhone.

Update macOS on Mac

Access the Apple menu and choose System Preferences.

From the System Preferences window, click Software Update.

Click Update Now or Upgrade Now.

“Update Now” will install the latest update for the Mac operating system installed. “Upgrade Now” will install the latest Mac operating system.

Update iOS on iPhone

Plug your iPhone into a power source and connect it to the internet using Wi-Fi.

Open Settings.

Select General, then Software Update.

Select the one you wish to install if there are two update options.

Press Install Now.

If “Download and Install” is displayed instead, press it to install the latest update. Enter your passcode, then press “Install Now”.

Try Restarting iMessage

A simple app reboot might do the trick once you’ve verified that your devices have the latest OS installed. Here are the steps:

On your iPhone, launch Settings

Tap Messages

Deactivate the toggle switch beside iMessage

And on your Mac:

Launch the Message app.

Select Messages, Preferences, and Accounts.

Deselect the Enable Account under the Apple ID option.

After five minutes or so, turn on the iMessage app on both devices, then try again.

• Check Your Apple ID
• Ensure the correct Apple ID is listed by signing in to the Apple ID website:
• Navigate to Apple ID and sign in to your account.
  

Go to Reachable At and check that your Apple ID and mobile number are listed. Otherwise, add those details.

• Try rebooting your iPhone and Mac to see if the messages have now synced across.
• Try Sending an iMessage From Your Mac

There may be a delay in updating your Mac, so try sending one from your Mac to help trigger the sync. Here’s how to send an iMessage from your Mac:

• Launch the iMessage app and sign in to your Apple ID account if prompted
• Click on the New Message icon
  

Type a name, number, or email address for a recipient to send a test text message. Or use the Add button to choose from your contacts.

Place the cursor in the message field to enter a message.

Hit Enter to send the message. Once the message is sent, it should prompt your Mac to start the sync process.