An official letter has specific features including addresses for the sender and recipient, a date, salutation, title or heading, body, and complementary close with signature. Important characteristics of an effective official letter are simplicity, conversational style, clarity of goal, positive public relations, use of "you" attitude, courtesy, persuasiveness, sincerity, positive language, proper emphasis, coherence, cultural sensitivity, tactful approach, ethical standards, and being brief but complete. Examples of official letters include sales, order, complaint, adjustment, inquiry, follow-up, recommendation, acknowledgment, cover, and resignation letters.