What type of mail requires both sender and addressee signatures?

Registered mail requires both the sender and addressee signatures as part of its security and tracking features. This type of mail is specially handled and provides the sender with proof of mailing and the recipient with proof of delivery. Each step in the delivery process is carefully documented, which is why it requires signatures at both points. The sender’s signature is recorded when the mail is sent, and the addressee's signature is collected upon receipt, ensuring that the item is securely delivered to the intended recipient.

This thorough tracking system makes registered mail a key option for sending valuable or important documents where confirmation of delivery is essential. Other types of mail, such as First-Class, Priority, and International mail, do not mandate both signatures for their processing and delivery. While some of these services offer tracking features, they do not require the same level of security and confirmation that registered mail does.