You can view your billing information and download invoices all on one page.
Only a user with Billing Permissions can view the billing settings.

Scroll down to the Invoice History section and click on the symbol next to the date to open the invoice:

Click on Download invoice or Download receipt:

What's the difference between an invoice and receipt? They display the same information in a similar format, but a receipt will show if the bill has been paid. Your finance department may prefer one or the other, but they're largely the same.