To view invoices go to Management console and click on Billing.
The second table on the page will show a list of current and past invoices along with some basic information. You will have the option to search invoices or sort by any of the columns in ascending or descending order by clicking on the column header. An arrow will appear next to the header name (up for ascending and down for descending). To download a copy of the invoice to your device click on the row.