I am tracking mileage using QuickBooks but how do I show the costs involved in my profit / loss? At present my travel is zero but I have recorded 800 miles

Hello there, @nomisskent.

Tracking your mileage in QuickBooks Online (QBO) makes it easy for you during tax time because you'll have a detailed log of all the business miles you can deduct.

The cost involve in your mileage will not automatically show in your Profit/Loss report. You'll have to record an expense transaction first (indicates information of the recorded 800 miles) to make this possible. Let me guide you how.

1. Select + New button.
2. Select Expense.
3. In the Payee field, specify the name of a person or a business. If your transaction covers multiple petty cash expenses, leave this field empty.
4. Select the Payment account to which to credit this expense.
5. Enter the date of purchase in the Payment date field and the Payment method.
6. (Optional) Enter a description of the expense.
7. Enter the amount of the purchase and any Tax paid (if applicable).
8. Select Save and close or Save and new.

Once done, you can now pull up your Profit and Loss report to view your mileage cost. Then, you can customise it to focus on the details that matter the most to you. After that, you can have it memorised to save its current customisation settings. Fro the detailed steps, you can refer to this article: Memorise reports in QuickBooks Online. 

Please let me know if you have other concerns. I'm just around to help.