If you GEDCOM by email (or any other way), part of your Uftree GEDCOM to the other person will not contain everything you have in UFTree. The GEDCOM coming in to you may contain everything sent but if you import the incoming GEDCOM you will find you than have duplicate individuals. That is a big mess to clean up.
You can, of course, enter information into an email letter or send text as an email attachment. Then the other person can key that information into his/her program. This is probably the best.
There is another even simpler way to send from you to someone else once you have set up UFTree to Print to File in .rtf. I just tested this by sending some reports to myself so I know it works.
There are two reports that can be Print to File that might be useful. If you have added information to an Individual or to a Family, Print to File an Individual Summary Report or a Family Group Report.
If you have added a lot of data and text to an Individual or to a Family, you wouldn't have to write it all into an email message.
Once you know how, just send the appropriate report as an .rtf attachment to your friend. That person would then print out your message and key (type) the information into his/her program.
I have no idea if your correspondent's program can do this in reverse.
If you need help in learning how to 'Print to File', see 3.0 small white manual, pages 132-134 top of page.
On the program CD is the full manual. There you want to study pages 151-153. I recommend printing out those CD manual pages before you try to Print to File. I find it easy to Print to File now, but I was quite confused at first.