does apple have an email app for iphone 12pro?

Yes. The Mail app is one of the built-in apps.

With iOS 14, apps can be removed from the home screen without being deleted. 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 is not in the App Library, it may have been deleted. To add it back, 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

1. On your iOS or iPadOS device, go to the App Store.
2. Search for the app. Make sure that you use the exact name of the app. Find the correct name of built-in apps.
3. Tap  to restore the app.
4. Wait for the app to restore, then open it from your Home screen.

Yes its pre-installed, but can be deleted. You can redownload it form the App Store here: https://apps.apple.com/us/app/mail/id1108187098

If it has the word “Open” instead of a cloud with an arrow pointing down, it means its installed on the iPhone. It may have been moved to the App Library.