To add a One-off Attachment the Invoice need to first be created and saved. Once you have saved the Invoice you can edit it and add one-off attachments.
 

  1. Open the Invoice you would like to add the attachement to.
  2. Click on the Attachments tab.
  3. Add your Attachments.
  4. Save the Invoice.
  5. The attachments will appear on the second page of the Invoice PDF