Thanks for considering Aspose.
First of all, let me share some information regarding Aspose.Pdf. It is a component which provides the capability to generate the Pdf file from scratch.
In case you need to manipulate/edit any existing Pdf file, then Aspose.Pdf.Kit is a component which offers you this functionality. Please visit the following link for information on difference between two components. Aspose.Pdf vs Aspose.Pdf.Kit
Regarding your query, I am not sure, which sort of information you would like to add to the document. If its some sort of watermark, then you can use PdfFileStamp for this purpose. You can add text, image and other Pdf file's page as Stamp. For more related information please visit http://www.aspose.com/documentation/file-format-components/aspose.pdf.kit-for-.net-and-java/add-watermark.html & http://www.aspose.com/documentation/file-format-components/aspose.pdf.kit-for-.net-and-java/add-logo.html
Aspose.Pdf.Kit also provides the interface to Print the Pdf file. PdfViewer Represents a class to view or print a pdf. For more related information, please visit http://www.aspose.com/documentation/file-format-components/aspose.pdf.kit-for-.net-and-java/pdfviewer.html
FYI : This is Beta version of PdfViewer. Some features may not be supported well and we may be not able to fix them in short time
If it still does not answer your query, please share some more details, and we would be pleased to acknowledge.