Service of a paper, other than a process, upon the sheriff may be made by delivering it to the sheriff, a deputy, or a person in charge of the office during office hours or, if none of the enumerated individuals is there, by leaving it in a conspicuous place in the office.
Service Of Papers On Sheriff
Mont. Code Ann. § 7-32-2124, under Sheriff's Office.
Mont. Code Ann. § 7-32-2124