There is an option to display the status stamp of your invoices in the PDFs as well as when taking print outs. To enable it, navigate to Gear icon -> Templates -> Invoices and select the Edit button on the template on which you wish to display the stamp.
In the Customize Template page, under the Header & Document Information tab, select the checkbox against the Show Status Stamp option and click Save for the changes to take effect.
Henceforth, whenever the status of an invoice is changed to Paid or Void, the stamp for the same will be available while downloading the PDF or taking a print.
and GST filing.