Reports/Customers/Sales/Reports
General client report
The customer report can be generated from the Reports functionality.
Select Report Type, Customer and the desired time period needed that you want to see on the report. A report with all clients will be generated; Simply search for the client you need to see the report.
Customer Profile Report
Go to the customer profile and click on the Invoices tab.
If you have invoices with different currencies you will also need to select currency. By default the given report will be from your base currency which is set in Setup -> Finance -> Currencies.