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I want my iPhone and iPad to delete messages at the same time instead of having to delete messages in each device separately.
iPad, iOS 12
Question marked as
Turn on messages in iCloud - Keep all your messages in iCloud - Apple Support. That syncs all messages, and any deletions you make across all your devices. Note however with messages in iCloud, when you delete a message, there is no way to recover it if you Later decide you did want to keep it.