Amazon icon

Assuming you didn't delete the app.. and you accidentally removed the app..

From your Home Screen, swipe left until you get to the App Library.

Swipe downward and you'll get an alphabetical list of your apps.

Locate the app in the list or type the app name into the search field

Once you've located the app, tap/hold, then drag it and it'll pop out to your Home Screen

Organize the Home Screen and App Library on your iPhone - Apple Support

If you can't find the app in the App Library list, then you'd go to the App Store and search for Amazon, then re-download it

Redownload apps and games from Apple - Apple Support

Lunabella61 Said:

"Amazon icon: My Amazon icon disappeared on my iPhone, how do I get it back?"

-------

If you can't Drag-&-Drop it...

Reset the Home Screen Layout:

If widgets are not working as they should or have gone missing somehow, then you need to reset the Home Screen Layout... Go Here: Move and Organize Apps on iPhone - Apple Support. You'd have to add back all the widgets that you can recall being back on there. So, write down what is currently on the Home Screen.

Scroll to: Reset the Home Screen and Apps to their Original Layout

1. Go to: Settings
2. Tap: General
3. Tap: Reset
4. Tap: Reset Home Screen Layout
5. Then... Add the apps back