Certified Mail
A USPS service that provides the sender with proof of mailing and electronic delivery confirmation, commonly used for legal and official correspondence.
Certified Mail is a domestic USPS service that provides the sender with a mailing receipt and an electronic record of delivery (or attempted delivery). It does not include insurance — for that, mailers must add Registered Mail or declare a value. Certified Mail is available only for First-Class Mail and Priority Mail.
At delivery, the carrier obtains a signature (unless waived by the sender), and the delivery record is stored electronically. Senders can add a Return Receipt (green card or electronic) to get a copy of the recipient's signature.
Certified Mail is widely used for legal notices, court filings, IRS correspondence, and debt collection because it creates a verifiable chain of custody. The USPS assigns each Certified Mail piece a unique tracking number in the format beginning with 7.