The stock Camera app cannot be completed deleted from your iPhone. It can be removed from the Home Screen however it will still reside in the App Library.
From your Home Screen, SWIPE LEFT and continue to swipe left until you reach the APP LIBRARY which is the last page. Locate the Camera app in the App Library. It may be in a folder described as CREATIVITY (There is a possibility that it may be in another folder). Once the Camera App is located in the App Library, then you can TOUCH & DRAG it out of the App Library and on to your favorite Home Screen.
Axel F.