Hi,
Thanks for your inquiry.
Sorry that there is no direct way to add PDF as watermatk. At present, Spire.PDF can add text or image as watermark. For your requirement, there are two solutions. One is drawing the text of header and footer into supplied PDF directly, here is the
guide for your kind reference. The another is converting the PDF as image, then drawing the image as watermark into supplied PDF. The
guide to convert to image, and the
guide to add image as watermark .
If there is any question, please let me know.
Sincerely,
Betsy
E-iceblue support team