How do you request a birthday card from the President for your grandmother on her 90th birthday?

It’s quite easy! Just write to the address below at least six weeks in advance of the birthday. Birthday cards will be
sent ten days before the birthday. In addition to requesting birthday
cards, requests can also be made for anniversary cards for
those celebrating 50 or more years of marriage. Here is the address:

The White House
Attn: Greetings Office
Washington, D.C. 20502-0039