To restore a missing app icon on an Android device, you can try these steps:

 

Check the app drawer

Look for the app in the app drawer and long-press and drag it to the home screen. 
 

Reinstall or re-enable the app

Open the Google Play Store, tap the profile icon, then tap Manage apps & device. Select the app you want to install or turn on. 
 
 
Reset app preferences
Go to Settings > Apps & notifications > See all apps. Tap the Menu icon, then tap Reset app preferences. 
 
 
Search for the app
Unlock the phone, swipe down to see the search bar, and type in the name of the app. 
 
The app might be missing from the home screen if it was deleted, disabled, or hidden.