I have a friend who has recently hit upon a way to send emails which appear to be from just about anyone he desires; in other words he can customize the From and Reply-To fields (as well as everything else, but these two are the current main concern) in the email. I am sure this is not difficult, but as I have little to do with email (all I ever use is hotmail and outlook), I really have no idea how it is set up, or how I could pull this off.
I wish to learn how to do this because this is the one and only area he has learned something which I do not yet know of, and am loathe to admit to him this fact. I am wondering if anyone could give me the basics of how this is done, and what is needed to do it; or if the information is already readily available, simply point me to an FAQ or a tutorial.
Thank you in advance!