I received this reply today from the UK. I had written to King Charles in November for his 75th Birthday.
The envelope is the usual from King Charles. The front features the new postmark that was updated a few months ago to reflect the Royal Mail's switch to Mailmark machines. And the back featured King Charles's coat of arms.
Inside is a folded card. The front of the card features King Charles's Cypher engraved in gold.
The inside features a photo of King Charles, along with a typed message and printed on signature. This is different than Charles's normal Birthday reply, because this is a milestone Birthday, his 75th. We saw a similar folded card for Charles's 70th Birthday.
Interestingly, King Charles did not choose a coronation photo for his birthday card. The photo is from The Scotland National Service of Thanksgiving and Dedication at St Giles' Cathedral in Edinburgh, Scotland. The photo was taken on July 5, 2023 by Chris Jackson.
The message is the typical sort. Expect this is the first time I've gotten a reply from Charles written in the first person.
The card says:
I am enormously grateful to you for thinking of me on my 75th Birthday and for sending me such a touching message.
This brings you my warmest good wishes.
Charles R