Lost Safari icon on iPhone 8

If you use screen time you may have it disabled which will cause the app icon to disappear.

Use parental controls on your child's iPhone, iPad, and iPod touch - Apple Support

If you don’t have it restricted and you can’t find it with the search as suggested by ThisIsPracticlyTheUsableName, you can reset the home screen layout in a Settings>General>Reset>Reset Home Screen Layout. That will return the app to the home screen but will also destroy the current app and folder structure that you have on your device res turning the home screen to out of the box condition..

It may just be lost on your home screen or in the 2nd page of a folder. Try searching for the app by swiping down slightly below the top of the screen in the home screen to pull up search menu.