Business letters are a formal way to communicate between organizations for various reasons such as introducing new staff, sending reminders, or issuing invitations. The standard format includes a reference line, date, recipient's address in capital letters, salutation using the recipient's name if known, subject heading in capital letters, text without indentation, closing ("Yours faithfully" or "Yours sincerely"), sender's name and position, and notation of any enclosures. Letters are typically sent by post or courier.