Required. A copy of any notice, order, pleading, motion, response, correspondence, decision, paper, or other document filed in a proceeding shall be served promptly on all other parties to the proceeding or, as authorized or required by COMAR 16.02.02.06, their respective authorized representatives. Manner. Unless otherwise required by law, service shall be made by personal delivery or by regular mail. Permittees, etc. Service on a party to whom a permit, license, or certification has been issued by the Department may be made by delivering a copy to the last address provided by that party to the Department. Proof of Service. Every paper or document filed in a proceeding, other than one filed by or on behalf of the Secretary, shall contain or be accompanied by a certificate of service. The certificate of service shall: Be signed by or on behalf of the party filing the paper or document; and Specify the: Date of service; Manner of service; Name of each person served; and Address at which each person was served.