If not sure that it was deleted, try using Search to see if that will locate it: Use Search on your iPhone, iPad, or iPod touch - Apple Support
Be aware that with iOS 14 apps can be removed from the home screen. If you have iOS 14, go to the App Library (swipe left past your last home screen). From there you can touch and hold an app and slide it left back to the home screen.
If it was deleted you can reinstall. See the following from Delete built-in Apple apps from the Home screen on your iOS 14 or iPadOS device or Apple Watch - Apple Support
Restore a built-in app that you deleted
- On your iOS or iPadOS device, go to the App Store.
- Search for the app. Make sure that you use the exact name of the app. Find the correct name of built-in apps.
- Tap
to restore the app. - Wait for the app to restore, then open it from your Home screen.