When you open the VA Forum - on the blue line which indicates your name and that you are signed in - go to the right on that line and you will see MY CONTROLS. Click that and it will take you to your control centre, on the left under Personal Profile is the section where you can edit/add your signature.
There is a limit to the number of lines etc - on the VA forum page near the top is the Forum Rules which details everything you need to know - including rules for signatures.
Thanks for the info-- I have updated my information! Only I don't see the information I added into the profile--maybe I have to restart the system? Not sure, will wait and see . . .