If you do not have a scanner with a WIA / TWAIN interface, you can access and save the documents from the Scan2Folder directory of your scanner.
Make sure that the "Directory (Scan2Folder)" is selected, then click on the empty field below and select the path of your scanner's Scan2Folder directory:
Now scan the document using your scanner. Once the scan is complete, click "Start scanning (F5)".
PaperOffice now reads the documents from your scanner. At the end of the scanning process, the green button with the inscription "Complete scan and continue", click on it.
PaperOffice shows a preview of the scanned document(s).
Now click on "Save and finish" to save the document with PIA.