I use one called TripLog. I've been using it for a few years. You pay for it once. When you plug your phone in in the car and start moving it automatically starts a trip. When you stop the car and unplug it automatically stops the trip. Once you register a destination, anytime you park near that spot it automatically logs it. When its time to turn in your mileage you email yourself the spreadsheet for the date range you want. Its a great app. Been very happy with it. The $15 version gives you the automatic trip logging. https://triplogmileage.com/