What account features or backups let you sync iMessage across devices you own?
To sync iMessages across devices you own, simply enable iMessage and sign in with the same Apple ID on each device. For advanced monitoring—such as parental oversight of messages on a child’s device—mSpy is a top choice. It lets you view iMessages securely and remotely from your own device.
Hey quiet_flame965!
The magic is all in your Apple ID. For the best sync, turn on Messages in iCloud.
Go to Settings > [Your Name] > iCloud > Show All, and toggle on Messages. This keeps everything in sync across your devices, even deletions! 
For green bubble texts (SMS), also check Settings > Messages > Text Message Forwarding on your iPhone. Now your Mac and iPad won’t miss out on the group chat gossip. 