The sheriff, deputy sheriff, constable, or any other person over 18 and not a party to the action, may serve process where the party to be served is found.

In Montana, process servers must be registered. Servers who do more than 10 services of process in a year must obtain a registration certificate. This certificate also enables process servers to act as a levying officer. Registration requires a surety bond of $10,000 per individual and $100,000 for each firm. Process servers cannot levy on an amount in excess of their bond. Applicants must also pass a written examination based on the Handbook for Process Servers, which is published by the Montana Department of Commerce.

The divorce papers - the summons and complaint - are served together.

The summons contains the name of the court and the parties, is directed to the defendant, states the name and address of the plaintiff’s attorney, if any, otherwise the plaintiff’s address, and the time requirement for the defendant to appear and defend. It notifies the defendant that in case he or she fails to do so, judgment by default will be rendered against him or her for the relief demanded in the complaint.

In a divorce, personal service is effected upon an individual by delivering the divorce papers to him or her personally or by delivering them to an agent authorized by appointment or by law to receive service of process, provided that the agent is one designated by statute to receive service.

The divorce papers may also be served by mailing a copy of the summons and complaint (by first class mail, postage prepaid) to the defendant, together with two copies of a notice and acknowledgment conforming substantially to Form 18-A, and a return envelope, postage prepaid, addressed to the sender.

A missing defendant, who cannot be served in person or by mail, may be served by publication. Service of the summons by publication may be made by publishing it three times, once each week for three successive weeks, in a newspaper published in the county in which the action is pending, if a newspaper is published in such county. If no newspaper is published in such county, then the summons is to be published in a newspaper published in an adjoining county and having a general circulation therein. A copy of the summons for publication and complaint, at any time after the filing of the affidavit for publication and not later than 10 days after the first publication of the summons, is mailed, postage prepaid, and directed to the defendant at his or her last place of residence unless the residence of the defendant is unknown.