Hello there, let me share some information about adding vehicle as primary in QuickBooks with your co owners.
In QuickBooks, only one profile can designate a primary vehicle. Thus, two profiles on the same account cannot track their mileage separately or have their own primary vehicle. When you categorize them, other users can also see and select vehicles.
Additionally, you can check this article for more details: Learn how to record business miles for one or more vehicles.
Keep me posted about your concerns with the mileage. I’ll be around in this forum to assist you.