We have tested these software vendors and approved them for use submitting Montana Annual W-2 1099 Withholding Tax Reconciliations. We only test software to ensure we can accept forms filed by the software. We are not associated with vendors and cannot guarantee any aspect of the software. Learn more about software approval from the IRS. Approved Software Vendors AATRIX ADP Black Mountain Software Ceridian Greatland Intuit QuickBooks Paychex Paycor Accounting CS If you need assistance with one of our online services, please email us at DORCustomerAssistance@mt.gov.