Hello, jlacombe87. 

QuickBooks Online equipped with tons of different reports that you can use to get a snapshot of your business. You can run the Transaction List by Customer. It contains the payment made and the total amount of the invoice. However, it won't show which invoices made the down payment. 

Here's how to do it: 

1. Click the Report menu. 
2. Enter the Transaction List by Customer in the search bar. 
3. Tap the Customize and modify the Report period.
4. Under Filter, Mark check the Transaction type, Customer,Payment Method and Amount. 
5. Press Run report. 

You can also export the report to Excel to come up with the data you need. Just click the Excel button at the top of the report and select Export to Excel. 

You can browse through these articles to learn more about what the report can run and how to use it:  

• Available reports in QuickBooks Online.
• How to customize reports. 
• Customize Reports and Email. 

Come and visit us again if you need help. It will be my pleasure. Stay safe and have a great day ahead!