The person who uploaded the file and the Team Admin are able to delete the file.
1. Select the file you wish to delete and click the [...] icon and [delete].
1. Go to the file detail page of the file you wish to delete. Then select the [...] icon and [delete].
However, comments will still remain undeleted so later on, other team members can understand work history and workflow. If you want to delete the comments as well, person who commented has to delete it him/herself.