Purporse is: status, familiarity wich subject, language.
Types of business documents is: call to action, internal, memo, status.
Types of communication is: tone, formality, language, plan and organise message.
The letter head is: company name, address, the signature, city, the initials,
the salutation business letter:
Dear Miss Trump:
Dear Mrs. Brown:
Dear Mr. and Mrs. Hill: