Sorry if this isn’t the right place for this question, but I’ve Googled high and low and found nothing.
I’ve noticed that some letters start and close with handwriting, e.g. “Dear Mrs Smith” and “Yours sincerely, Mr Smith” will be hand written, while the rest of the letter is typed by computer/typewriter.
Examples are the Prime Minister of the UK and from the Queen’s staff at Buckingham Palace. See photos below.
Is there a name for this style? When is this style appropriate? I really like it, because it seems more personal. Could I adopt this style myself?