Md. Rule 11-107
Rule 11-107. Service of Papers
(a) Summons. A summons issued pursuant to Rule 11-106 shall be served in the manner provided by Rule 2-121, and be returnable as provided by Rule 2-126.
(b) Other Papers. Except as otherwise provided by law, all other papers filed with the court, other than a petition or citation, shall be served in the manner provided by Rule 20-205.