You'll want enter on Car and Truck Expenses Worksheet.  There you'll be able to enter mileage to support the 100% business use.  Also you can elect to deduct actual expenses or standard mileage on that worksheet.   As @Terry53029  pointed out, you may want to consider what's the best option based on how much mileage will be.    Sec179 may give you nice write off the first year but how will actual look compared to mileage in future years?