Certified Mail is a service offered by the United States Postal Service® for a fee in addition to postage. Sending Certified Mail provides a delivery record that the Postal Service keeps for two years.
You can choose the Return Receipt service when you use Certified Mail. For an additional fee the Return Receipt assures that you have legal proof of receipt of the communication: The Postal Service sends the green return receipt postcard back to you, the sender. This is a very useful tool for collecting funds, recovering checks and making legal notifications. A return receipt for Certified Mail serves as a legal document proving the date and time when the recipient took possession of the mail piece.
If you decide you want a return receipt after you mailed your certified mail piece, go to your local post office and ask for this service. The post office will give you a scanned image of the recipient’s signature, along with the date of delivery. Be sure to provide the 22-digit barcode used on the mail piece.
You can eliminate the traditional "Green Card" and save money as well by using the Electronic Return Receipt (ERR) option on your system.