While iOS 10 brought the ability to more or less hide iOS built-in apps, you can actually delete with iOS 11.
Deleting the default iPhone apps is as easy as you would expect, it’s just like deleting third-party apps. You can’t delete all of the default iOS apps.
Deleting the built-in apps doesn’t really free up any meaningful space on your devices. You will better off checking out some of these options if that’s your goal. Removing built-in apps is more of organizational and personal preference.
How to Delete and Restore Apple’s built-in apps on iPhone:
1) Tap and hold an Apple app that you would like to delete.
2) when the app begins wiggling, let go and tap on the close button in the corner of the app you would like to delete.
3) Confirm you would really like to go through with it by tapping delete.
How to restore Apple’s built-in apps on iPhone:
1) launch the App Store.
2) Tap search in the bottom right-hand corner.
3) Type the default name app exactly as Apple spells it and look for the apps without any ratings.
4) Click the icon to restore the app.
These are the ways which will help you with deleting and restoring default apps on iPhone.