How any parts are in a private letter?

একটি Letter এর ৬টি অংশ থাকে।
1) The Heading (a) The writer's address b) The Date)
2) The Courteous Greeting or Salutation.
3) The Body of the Letter
4) The Subscription or Courteous leave-taking
5) The Signature
6) The Superscription (Receiver Address) on the Envelope or Postcard.

Source: High School English Grammar and Composition by Wren and Martin এবং Applied English Grammar and Composition - P.C. Das.