I receive a document in pdf that I need to digitally sign (I have adobe pro). How to electronically sign and forward pdf without having to save it and reattach it.
By signing you mean using a digital certificate?
When you open a PDF from an email it doesn't exists in a real file location, so when you do something like signing it needs to save it somewhere. Actually the file does exists in a temporary location, but for all practical purses its just in space.