Iowa Code § 618.15: Service by certified mail.

Wherever used in this Code, the following words shall have the meanings respectively ascribed to them unless such meanings are repugnant to the context:

1. The words “certified mail” mean any form of mail service, by whatever name, provided by the United States post office where the post office provides the mailer with a receipt to prove mailing.

2. The words “restricted certified mail” mean any form of certified mail as defined in subsection 1 which carries on the face thereof, in a conspicuous place where it will not be obliterated, the endorsement “Deliver to addressee only” and for which the post office provides the mailer with a return receipt showing the date of delivery, the place of delivery, and person to whom delivered.