There seems, may it please your Majesty, to be a mighty contest between Great-Britain and North America! Queen Elizabeth II was an important figure of the world for over half a century.Her successor King Charles III became Monarch on the 8th of September 2022. It depends how well you know the person you are writing to. For the British royal family there is a guide on the Royal family page. "What do you say when addressing the king? On presentation to The King or Queen, the correct formal address is 'Your Majesty'. Any letter to The King or Queen should be addressed to 'The Private Secretary to His Majesty The King'. The Queen receives 1000s of letters annually, but what must you do when writing a letter? Here's a guide how to write to the Royal Family.