Acknowledge letter:
1. It is a receipt and a public relation tools.
2. Objective is to let the reader know that items requested in a prior communication.
3. The scope can actually be brief, just enough to complete a business communication cycle.
4. Maintain business relationship
Announcement letter:
1. This letter announces a special event that people need to be aware of.
2. Usually formal, state in clear.
3. Two types of announcement letter