Thanks for joining the Community, LizDebenham.
You can create custom travel rules to tell QuickBooks when a trip takes place. You'll also be able to enter starting/ending points and mark if your mileage is business-related or personal.
Upon arriving at the destination, your books will prompt you to categorize the trip. Your app can also be used to see detailed reporting/potential tax savings estimates. Trips can be reviewed by going to your Mileage or Trips menus, then selecting All or Reviewed.
I've included a couple detailed resources about using our mobile application that may come in handy moving forward:
Please feel more than welcome to post a reply if there's any additional questions. Enjoy the rest of your day!