If you don’t know your legislator, the Montana Free Press has an easy to use interface to find legislator contact information if you know the name as well as find your legislator by your address if you don’t:
https://projects.montanafreepress.org/capitol-tracker…/…
Similar functionality but not as easy to use at state website:
https://www.legmt.gov/ and click on Legislators
The easiest way to contact a legislator about a bill is to call the Capitol switchboard and leave a message. 406-444-4800 You can also leave a message for multiple legislators or entire committees or houses.
If you prefer to contact your rep or senator by email or US mail you also can find that information at https://www.legmt.gov/ and choose Legislators.
The Montana state legislative website also has a “Participate” feature that allows people to contact individual legislators, committees, and entire houses through a form interface. Or even sign up to testify. An account is required.