Cannot delete file, it is currently in use.

Hello,

To correct this, you will need to clear the cache for Word app. To do this, follow these steps:

Close Word for iPad

1.        Double tap the Home button.
2.        Select the Word for iPad app from the list of open apps.
3.        Drag the app toward the top of the screen to close it out.
   

Reset the Word for iPad app

1.        Ensure that the Word for iPad app is closed by viewing the list of open apps.
          (Follow steps 1 and 2 from above to view the list of open apps).
2.        Open Settings by clicking on the gears icon.
3.        Within Settings, tap the Word app.
4.        Next, scroll to the bottom of the Word for iPad settings and tap Reset Word.
5.        Then, tap the Clear Document Cache option.

After clearing the cache from the Word app, open the Word for iPad app again and verify that the file is no longer listed. 

For more information or support regarding Office for iPad, please visit the following link.
Set up Office for iPad with Office 365 for business