Discovery

Discovery refers to a pretrial proceeding where a person has the chance to learn information that is known by the other person in the case or other witnesses.  Parties can obtain discovery through methods such as depositions, production of documents or things, permission to enter upon land or other property for inspection, and more.

A commonly-known method for obtaining testimony and/or documents from another persona is a Subpoena, which is a written legal notice requiring a person to appear in court and/or give testimony or produce documents.

The rules and deadlines governing discovery are outlined in the Montana Code Annotated, under the Rules of Civil Procedure.

General Guidance (not specific to Montana)

How to Subpoena Witnesses, article from Nolo.com

How to Subpoena Documents, article from Nolo.com