Viewing statements
To view a customer's statement, go to the customer's page, click Orders, credit notes & payments, and click the smaller Actions dropdown button under the Unallocated account payments/credits section, where you'll find the View account statement button.
You can then choose to export the statement by selecting Export and then either Outstanding only or a Full statement. You can manually email it to the customer from here by selecting Email to customer.
Automatically emailing statements
To have customer statements sent automatically to customers, head to Settings -> Email settings -> General email settings. You will then be able to set up automatic emails to all customers for outstanding invoices. You can also choose in your settings here whether you would like to send a PDF or Excel format statement (or both).
