There is no guarantee, but Harry and Meghan are known to send thank you notes to hose who mail them.
Those who sent well wishes following the Sussex's wedding received a message back featuring a black-and-white portrait of the newlyweds.
Circulating social media at the time, the cards featured the official Kensington Palace crest and featured a short note that read: "The Duke and Duchess of Sussex have been overwhelmed by all the incredibly kind cards and letters they have received on the occasion of their Wedding, and are so touched that you took the trouble to write as you did.
"It really was most thoughtful of you and greatly appreciated by Their Royal Highnesses who send you their very best wishes."
The Sun reported that everybody who sent the royal couple a message received a printed thank you note.