Invoice list
You can find any invoice issued in the instance through the Tools > Receipts list menu:

This tool lets you obtain a list of results with all the invoices issued by your institution, according to certain criteria such as:
Invoice issuer
You can obtain a list of all the invoices issued by a given invoice issuer.
Expense center
Find a list of invoices that belong to the same expense center. You can find this expense center by its name or by its identifier.
Dates
You can narrow down the list of invoices by date ranges or by issue start or end dates.

The resulting list shows the invoice reference code, the issue date, the buyer and the option to download or delete the invoice. The list can also be exported to Excel, where more specific details of the invoice and the attendee are shown.