Stamping a PDF Portfolio?

Hi guys

I've been reading about portfolios recently and i just want to really get a direct answer from experts out there.

is it possible to stamp the pdf files inside a portfolio? I have one file with emails and pdfs inside and cant seem to get the usual sidebar with options like fill & sign, stamping and all other options we usually have for normal pdf files.

Could someone help me out on this one please. Appreciate it a lot!