What must be included on the envelope for certified mail?

The correct answer is that a request for return of letter must be included on the envelope for certified mail. When sending certified mail, it is essential to indicate the need for a return receipt. This serves as proof that the letter or package was received by the intended recipient. The recipient's signature on the return receipt can provide valuable confirmation for the sender, especially in legal contexts.

Including a return address on the envelope is sometimes a standard practice for mail but is not specifically required for certified mail. The witness's name and a tracking number are not requirements for the envelope itself. While a tracking number is generated for certified mail to monitor its status during delivery, it is typically not something that needs to be explicitly marked on the envelope itself. Thus, the emphasis on a request for return of letter is vital to uphold the legal necessity of documentation regarding delivery.