How can I retrieve messages from my iPhone 12-- old deleted ones

Go to Settings/[your name]/iCloud. Is the switch for Messages turned on? If it is, you cannot recover the messages.

If it is off and you have a backup made before they were deleted you can restore that backup, but note that it will overwrite everything on your phone with whatever was in that months-old backup, not just the messages. And also note that backups are incremental, so unless you haven’t backup since that old backup the messages won’t be in it.

Hey There 🙋🏽‍♂️

Once you delete your Messages the most assuring way to retrieve them is by Restoring an iCloud Backup, if your Messages app is turned on in your iCloud Backup. If you have an older Backup file either on your iCloud or on your Computer, you'll be able to restore your information and messages back to that date.

If that's not the case you can always contact your Operator/Carrier. They might store deleted messages and be able to help you.

If you still need further assist with that matter feel free to contact Apple Support

Hope that helps !

Best,

~Aryan

If you mean text messages there is no way to recover them.