Hello, jjules. 

Thank you for reaching out to the Community. We can run Transactions List by Vendor report. This report shows the transactions( income and expense) assigned to the project. You can customize it by following these steps: 

1. Go to Reports on the left panel. 
2. Enter Transactions List by Vendor in the search bar. 
3. Select the Report period and click the Customize button. 
4. Click Filter, and select Expense from the Transaction Type drop-down list. 
5. Press the Run report button. 

I've got these articles for reference: 

• Customise reports in QuickBooks Online. 
• Export reports, lists, and other data from QuickBooks Online. 
• Reports included in your QuickBooks Online subscription. 

The Community will always have your back if you need anything else in running your business in QBO. Assistance is just one post away. You have a good one.