The Maryland Affidavit of Service (Certified Mail) is a notarized document used to verify that legal paperwork was received by an individual or entity. This document is used to provide proof of delivery of documents through the United States Postal Service (USPS) Certified Mail. There are two types of Maryland Affidavit of Service (Certified Mail): the Return Receipt and the Electronic Return Receipt. The Return Receipt is a physical document, usually green, that is returned to the sender as proof of delivery. The Electronic Return Receipt is an email notification sent to the sender as proof of delivery. The Maryland Affidavit of Service (Certified Mail) must be completed by the sender and signed in front of a notary public to be valid. It must include the date of delivery, the name and address of the recipient, and the name of the notary public. It must also include a detailed description of the documents that were sent.