Montana requires the original physical title document to register your vehicle. Electronic titles ("e-titles") are not accepted - neither are copies, scans, or photos of a title.
Several U.S. states issue or hold titles electronically by default. If your seller's title is held electronically by that state's DMV, your seller will need to request a paper title from that DMV before sending it to visitor.us.
Once the seller has the paper title in hand, your seller can complete title assignment and send it to visitor.us as described in Step 2e: Your vehicle's prior title.