An app icon has disappeared from the home screen. What can I do?

Please try the below:

1. Third-party themes or plug-in won't have app icons on the home screen, so check the download files for them.
2. Restart your phone to refresh your home screen.
3. Uninstall and reinstall the app in question.
4. Swipe up the home page to open the application center and long-press on the app to drag it to the home screen.