Launch the Shortcuts app on your iPhone or iPad.
Tap the + icon in the top-right corner of the screen.
Tap Add Action.
Use the text field to search for Open App.
Select Open App.
Use the search for the app you want to change the icon of, and select it.
Tap the three dots in the top-right corner.
Tap Add to Home Screen.
Tap the placeholder app icon.
From the drop-down menu, select Take Photo, Choose Photo, or Choose File, depending on where your replacement app icon image is located.
Select your replacement image.
In the text field, rename the app as you want it to appear on the home screen.
Tap Done. Your Shortcut has now been created.
Return to the home screen.
If you already had the app on your home screen, you will now have two icons. In order to keep only your newly-created icon, simply move the old icon to the App Library. You must not delete the original app.