Via the notification on batch change

  1. Retrieve the value of the vads_ext_trans_id field.
    This value corresponds to the Klarna invoice number (also called ocrNumber).
  2. Concatenate the URL of Klarna with the value of ocrNumber and the .pdf or .jpg extension as follows:
    https://online.klarna.com/invoices/%22ocr number.pdf or jpg
    The merchant can also retrieve the invoice in the PDF or JPG format and, if needed, send it to the buyer.
    The URL remains available for a period of 30 days.