Which region of Desktop are you using? If it is the UK version, there are no sample reports or accounts available. Your only options would be to either create a trial and enter data so you can run a P&L, or create a sample company file if you already have Desktop and do the same.
There are different reports that we can pull up for the invoices with class. I'll pull up and customise the Sales by Customer Detail report as an example.
You can export the report to Excel if necessary.
Get back to us if you want a different report. Have a great day!