1. First search on the desktop of Xiaomi phone: slide left and right on the desktop to see if it is hidden in other folders. If you find it, you can long press the icon and then drag it to the desktop. It can be restored.
2. Finally, search in the settings of the Xiaomi phone: open the "Settings" application on the phone and click "Application Management". Find the "SMS" application in application management and click to enter. In the SMS application, find the "Desktop Shortcut" option and click to enter. In the desktop shortcut, find the "Add to Desktop" option and click on it.