Business letters are letters written in formal language, usually used when writing from one business organization to another, or for correspondence between such organizations and their customers, clients and other external parties. The overall style of letter will depend on the relationship between the parties concerned.
Business Letters, in the United States, usually contain the following information, in this sequence:
• Letterhead or sender’s address
• Inside address
• Salutation or Greeting
• Signature, printed name, and position of sender
There may be circumstances when the business letter may also include the following optional information:
• Reference (RE:)
• Carbon Copy Recipients (CC:)
• Enclosures (ENC:)
• Reference Initials (of the typist)
Definition of Business Letter.
You can find various examples of Business Letter here.