How to remove display message from my iPhone?

Santavalerio wrote:

How to remove display massage

If you have never had the display serviced or replaced, that message can mean there is something wrong with it. Contact Apple and have them evaluate it:

Genius Bar Reservation and Apple Support Options - Apple

If you have had the display replaced by someone who isn't Apple or an Authorized Apple Service Provider, you can't remove the message. You can ask Apple if they would be willing to replace the display (for the repair cost) but, as the phone has already been opened by an unauthorized person, they may refuse.