You can share files with a different Account when they are uploaded to the wrong account.
- Click Files on the left-hand navigation
- Filter by the Account or Contact name associated with the files to narrow down the list
- Click the checkboxes next to each file that needs to be moved
- Scroll to the bottom of the page and click Share File
- In the To field, choose only the Account the file needs to be moved to
- Click OK
- Click Share