how to append header and footer exiting PDF.

see this article

http://www.c-sharpcorner.com/blogs/adding-a-header-or-footer-to-pdf-in-c-sharp

http://www.mazsoft.com/blog/post/2008/04/30/Code-sample-for-using-iTextSharp-PDF-library

Dear Sagar

i am using this code as well but my data had lost when i run this code

Hi Deepak,

Visit below link hope you find your solution :-

https://gopalkaroli.wordpress.com/2011/11/12/how-to-add-header-and-footer-on-pdf-file-using-itextsharp-5-1/

Hope helps..