Swipe down on the Home Screen and use Spotlight Search
Check the App Library by swiping left past the last Home Screen page
Look inside folders on the Home Screen
Open Settings > Screen Time > Content & Privacy Restrictions
Open Settings > Screen Time > App Limits
Open Settings > General > iPhone Storage
Check the Purchased list in the App Store
Open Settings > Home Screen to see if apps are set to App Library only
Check whether apps are hidden from Home Screen pages by entering jiggle mode
Search for the app name in Settings search
Check for hidden apps in the App Store account under your profile
Look for apps with restricted access in Settings > Privacy & Security
Check if the app is offloaded in Settings > App Store
Restore hidden Home Screen pages by entering edit mode and tapping the page dots
Search within Messages, Mail, or Files if the app stores content there