If you plan to charge your customers for your mileage expenses, you must
create a service item or an 'other charge' item for the mileage
expense. You can use either item type, depending on how you like to set up your
expenses in QuickBooks.
When you set up either item, you can:
Set a fixed rate to charge your customers, such as for a fixed delivery
Leave the rate blank if you will charge varying fees for a reimbursable
expense, such as only charging the actual mileage expense.
other charge item
Charging a customer for mileage