On which iPhones does the Important Display Alert Appear and where?

You will see “Important Display Message” on iPhone 11 and higher ones if you get your screen changed from a non-authorized Apple repair service center. 

The alert will initially be displayed on the lock screen within the first four days after the replacement. Then, the same message will appear in the settings menu for another 15 days. Subsequently, it can only be seen in the settings under "General" > "About".

If you want to know how to remove “Important Display Message”, please check out our YouTube channel.