Scanned PDF file problem

Hello,

Good Afternoon.

I am using windows 10 & Nitro pro 9. I have received a pdf document of 10 pages from my friend ( he is using apple mac book, google account) . I printed first 2 pages & signed , chop a stamp. I scanned these signed 2 pages and replaced with old 2 pages in the same pdf file. after that I sent this file to same person via email ( apple mac book & gmail account), the file shows wrong information. I mean, my sign & stamp will not be there on the pdf document(first 2 pages). it shows clean doc without stamp & sign as a previous file.

if any one knows, how it solve. pls tell me.

I hope that you understand my problem..

Thanks,
Ganesh