There are three ways to identify the senders of certified mail, the first being to look at the included green card filled out by the sender on the piece of certified mail received, according to the Houston Chronicle. The back of the card has the sender's name and address.
If the intended recipient is not available to accept delivery, the postal worker leaves behind an orange slip. The identity of the sender should be indicated in the top right-hand corner. If a person is not available for delivery and the identity of the sender is left off the orange slip, the recipient can contact the post office and ask for the sender's identity using a tracking number on the "not available for delivery" orange slip.