When using Drupal and UberCart, I can view an invoice by going to: admin/store/orders/10006/invoice, but…. clients can’t access this, even with the “view own orders” permission.
Is there a way to either give them access to only that link, or an alternative link where they can view it?
They should be able to see it from their user account page. There is a ‘My Orders’ or ‘My Order History’ tab that will show previous orders as the invoice.