Swipe down on the Home Screen and use Spotlight Search to find the app
Check the App Library by swiping left to the last Home Screen page
If the app is on a hidden Home Screen page, press and hold the Home Screen, tap the page dots, and reselect the hidden page
If the app was removed from the Home Screen, find it in the App Library, press and hold it, then tap Add to Home Screen
Check Screen Time restrictions in Settings
Check whether the app is hidden in App Store purchases
Open Settings, tap Siri & Search, select the app, and enable Show App in Search and Show on Home Screen
If the app is inside a folder, open the folder and look for it there
Restart the iPhone if the app still does not appear
Reinstall the app from the App Store if it was deleted