When you enable Lost Mode for a personal item with a connected AirTag or a supported third-party product, you can send a message with your phone number or email address. If your AirTag is discovered, the message can be viewed by pressing and holding the top of their iPhone or NFC-capable smartphone to the AirTag to access found.apple.com. If a user discovers your compatible third-party product, they may open the Find My app, pick the Items tab, hit Identify Found Item, and select the item from the list to view your message.