What service is characterized by allowing tracking and proof of mail delivery?

The service that is characterized by both tracking and proof of mail delivery is the Accountable Extra Services Mail. This option encompasses services such as Certified Mail, Registered Mail, and insured mail, which provide verifiable proof of delivery. When using these services, senders receive a receipt at the time of mailing and can track the item’s journey to its destination, ensuring that it has been received by the intended recipient. This identifies the delivery status and adds a layer of security and accountability for important documents and parcels.

In contrast, while Express Mail offers expedited shipping and some tracking capabilities, its primary focus is on speed rather than the comprehensive proof of delivery found in accountable services. Standard Mail, generally used for bulk mailing and advertising, does not typically include tracking or proof of delivery as part of its service. First-Class Mail offers better service compared to Standard Mail, including tracking options for certain types of items, but lacks the detailed accountability measures provided by the Accountable Extra Services Mail.