Tenn. Code Ann. § 7-3-504

Service by mail of a citation or civil warrant upon the violator may be made by any employee of a metropolitan government, by any additional plaintiff, or the violator's attorney, or by any person authorized by statute. The person serving the citation or civil warrant by mail shall send, postage prepaid, a copy of the citation or civil warrant to the violator by registered, return receipt, or by certified, return receipt mail. Service by mail shall not be the basis for the entry of a judgment by default unless the record contains a return receipt showing personal acceptance by the violator or by the violator's authorized agent.