Answer:
Heading.
Step-by-step explanation:
In any form of business letter writing, it is always necessary to put the date in the heading section of the letter. Since it is a formal mode of communication, the form of letter writing should also exude the business-like nature of the issue and should not be simply casually addressed.
The letter should start with the sender's address and contact details, followed by the date and then the receiver's contact details and address. Then comes the salutation followed by the body and complimentary close and the signature.
Format:
Sender's contact details
Date
Receiver's contact details
Salutation
Body
Complimentary close
Signature