Hello 3hatsfish-gmail-,
 
Welcome to Community!  QuickBooks Online provides reports for every area of your books.  These can be customized, so you can see what matters most.  I can understand the importance of reviewing your mileage.  I would be glad to assist!
 
I suggest making sure that Mileage Tracking is turned on.  To view the report, proceed to Mileage, then select Download Trip.  This opens the report in Excel, with all of the trips that have been entered. 
 
Should you require additional assistance, please don't hesitate to contact us outside of this forum. It would be our pleasure to work with you in real time, and ensure you're able to review your mileage report without delay!
 
Feel free to reach out with other questions. We are always glad to help!