Google Authenticator on iPhone 7 can not edit/remove entries
In the blue top bar with the "Authenticator" title, on the right you have the two buttons, one with a plus sign to add entries and one with a stylized pencil that allows you to edit the list.



Tap the pencil button, tap the circle on the left side of any entry you want to delete (the circle will fill red) and at the bottom of the screen a button to delete the selected entries will appear.