The letter just gave me a personalized code (seems tied to my name+zip code), and then a generic link to
www.applynow.citicards.com ... as an experiment, I tried using the code with a different last name + zip, and it said:
"The information entered does not match our records. Please be sure to enter it exactly as shown on your invitation letter."
I don't think there's any way I can share, or I definitely would! Sorry!