A document must reside in one folder, but may have been saved to additional folders. The Where Used list displays the original document location and all other locations it was saved to, if you have access to them. This removes the duplicate reference from the selected folder, it does not delete the item.  This requires Read/write access or higher. 

In the desktop view:

1. Select .
2. Highlight the document in the list.
3. On the right, select the Properties tab. 
4. Scroll down to Where Used. 
5. Select  to expand the list.
6. Select  to expand the list. 
7. Select x for each reference to delete.

In the mobile view:

1. Select the kebab menu  for an item in the list. 
2. Select More actions. 
3. Select Properties.
4. Scroll down to Where Used. 
5. Select  to expand the list.
6. Select  to expand the list. 
7. Select x for each reference to delete.