Final answer:
Certified Mail is the type of delivery that requires a recipient's signature upon delivery, offering a secure way to send important documents with proof of delivery. As digital communication becomes more prevalent, traditional postal service demand changes.
Step-by-step explanation:
The type of mail that requires your signature when it is delivered is Certified Mail. Certified Mail provides the sender with a mailing receipt and electronic verification that the mail was delivered or that an attempt was made to deliver it. It is often used for important documents where proof of delivery is required. Sending mail as Certified Mail is a way to ensure the mail is tracked and a record of the recipient's signature is kept. This adds a level of security to the delivery process and is beneficial when sending legal or time-sensitive documents.
Moreover, with changing preferences towards faster and more digital forms of communication, there has been a change in demand for traditional postal services, or what is commonly referred to as snail mail. The shift towards digital messaging impacts the volume and type of services required from the Postal Service.