Mont. Code Ann. tit. 25, ch. 24, Rule 10
Duty to make service
Rule 10 . Duty to make service.
(a) It shall be the duty of the parties when personal service is required of an order, warrant, summons, subpoenas, or any such order, to cause it to be delivered to the chief of police, sheriff or other qualified person for service.
(b) It shall be the duty of the parties in all cases to simultaneously serve their adversaries with a copy of all motions, pleas and briefs on the same day as filing with the court.