I am looking for a way to enter "expenses" such as miles so that it shows up in billing reports as well as on invoices.

I can walk you through the process to record a mile expense that will show on your billing reports and in the invoice, gmyers2125. 

To begin, you'll need to set up the mileage tracking feature in QuickBooks Online (QBO). You can either export the mileage data or manually add trips in the Mileage tab. It's important to set this up accurately, as QBO has a different way of calculating for tax and other purposes.   

When everything is set up, let's start recording the miles by using a bill or an expense transaction and entering it as a Category or an Item. 

If you decide to enter it as a category, you'll need to have a mile account. This account will hold all mile-related expenses you'll make in the future for easier and more accurate tracking. I also recommend consulting an accountant for additional guidance. They'll be able to provide you with suggestions on how to create this account. Here are the steps you need to follow:

1. Go to the Gear icon, then select Chart of Accounts.
2. Click the New button and enter the Account name.
3. In the Account type dropdown menu, choose an account, then pick a Detail type of your choice.
4. Put a checkmark to Use for billable expenses and set a desired Income account.
5. Hit the Save button once done.

However, if you select to enter it as an item, make a mile service item to record it.

Afterward, make the bill or expense billable by checking the Billable column and adding the customer's name in the Customer/Project field.

Once you're ready to bill this to your customer, you may now make an invoice and add the billable expense to it. 

Furthermore, QBO offers a variety of reports you could use to view your transactions and business status.

In addition to that, customizing these reports can also help you personalize them to fit your reporting preferences and needs.

With these guidelines, you can record the mile expense and display it on your billing reports and invoices in QuickBooks. However, if you require further assistance, don't hesitate to reach back. I'll be right back to help you out. Have a wonderful day!