1. The document discusses two types of official letters used in Bangladesh - W.I. Circular (W.I.C) and R.I. Circular (R.I.C). 2. A W.I. Circular contains confidential information that is communicated between government officials. It remains within the concerned department and is usually kept in the personal file of the employee. 3. An R.I. Circular publicizes notifications or information announced by the government for the country and its people, such as restrictions placed in an area due to law and order situation.