Hi again,
So while e-mail can be more informal, what about written letters? Like job applications, how would you start those? Dear Mr. Smith, if you know the person's name. Dear Sir or Dear Madam, if you don't know the name.
Put 'Yours sincerely' at the end, sign below, and print your name below your signature.
Can you use things like "I'd", "can't" in formal written letters or should everything be written like "I would" and "can not"? Write things out in full.
Best wishes, Clive