Click Receivables at the top of the page, then click Invoices.
Locate the invoice associated with the document you'd like to delete, and click the Invoice # to open.
Hover your cursor over "Invoice Details" (above the top left corner of the invoice image), and click Documents;
Click the name of the document you'd like to delete.
Click [show details] above the top left corner of the document image.
If you'd like to undelete this document, you can locate it in your Inbox History.