Hi jencomponents1m,

At this time, deleting multiple invoices at once  isn't possible in QuickBooks Online (QBO). You can manually delete an invoice one at a time. Let me guide you how.

1. Click Sales on the left menu.
2. Go to the Invoices tab.
3. Select the invoice that you want to delete.
4. Under the Action column, click the drop-down arrow and select Delete.
5. Click Yes.

Also, I'll pass this along to our product team to let them know of you business needs. 

I got this link in case you have other questions about QuickBooks Online (QBO): Sales And Customers.

Let me know if you need anything else. I'll be right here to help.