If this is for a business, @Michele C is correct in that to take the standard mileage deduction for a business, you want to limit the amount of vehicles used in each activity to 5 and under. That is the crux of the matter. So, for example, you can use 5 for one operation and the other 3 for the other operation.
This IRS article will also help in determining the difference between the standard mileage rate and the actual expenses so you can determine the best deduction.
If these are personal vehicles, the vehicle licensing fee paid for each personal vehicle can be deducted on Form 1040, Schedule A, Line 5c.
If you use your personal vehicle to incur medical transportation expenses for a child, nurse, or a patient who cannot travel alone, you can deduct the expenses of out-of-pocket costs for gas and oil. Or you can take the standard mileage rate for medical costs of 22 cents per mile in 2023. These expenses would be deducted on Form 1040, Schedule A, Line 1.
If you use your personal vehicle for volunteer work, you can deduct the charitable standard mileage rate of 14 cents per mile in 2023. If you prefer, you can deduct the actual cost of gas and oil incurred while doing the charitable work. Parking and tolls can be deducted here. A written log showing the dates and miles driven for each organization is required. These expenses would be deducted on Form 1040, Schedule A, Line 11.
[Edited 6/3/2024|2:54pm PST]
@ponysoo
