To delete files just follow the instructions:

  1. Enter edit mode by pressing the "Select" button in the upper right corner of your documents overview.
  2. Select the files you want to delete.
  3. Press "Delete" in the bottom toolbar. Have a look at the screenshot below.
  4. To exit edit mode just press "Done" in upper right corner.
iPhone showing files selected in edit mode with Delete button in toolbar
iPad showing files selected in edit mode with Delete button in toolbar