First Time Since He Was Born
From the first day he was born, Harry was referred to at His Royal Highness. However, this will no longer by the case. According to Buckingham Palace, the couple will not use their titles and will no longer be considered working members of the royal family.
Archie Mountbatten-Windsor
Even though the couple does not have their royal titles anymore, they will still be referred to as the Duke and Duchess of Sussex. However, Meghan and Harry decided that they did not want their son to have a title when he was born.