Swipe left until you get to the App Library, tap the search field and see if you can find the app. If you can, it's still on your iPhone.
OR
Swipe downward from any Home Screen and type the app name into the search field, if you can open the app from there, it's still on your iPhone.
OR
Go to Settings > General > iPhone Storage and if you find it there, it's still on your iPhone
OR
Go to the App Store and search for the app, if it shows 'Open', then it's still on your iPhone.
review this support article
How to delete apps on your iPhone, iPad, and iPod touch - Apple Support
- You can delete an app from your Home Screen by tap/hold on the app icon, when the menu pops up, select Remove App, then in the subsequent menu select Delete App
- You can delete an app from the App Library by locating the app and tap/hold, select Delete App.
- You can delete an app by navigating to Settings > General > iPhone Storage > [app name] scroll all the way down to the bottom and select Delete App.
If you are unable to delete apps with any of these methods, check:
Settings > Screen Time > Content & Privacy Restrictions > iTunes & App Store Purchases > Deleting Apps
make sure that's set to 'Allow'