Payments are backbone of the any business. You can received payments from customer by cash, offline accounts (set in settings page). Online payments are not available yet. We have plan to add online payment options using PayPal and credit/debit card payments with Stripe, PayPal Pro, PayPal Rest or Authorize.net in future updates.

Payments are attached to customers and can be requested from customers listing page as you need. Payments are not attached to orders. Orders will added the grand total to the customers balance. Payment request can be automatically generated for order and customer will get notification (if enabled) to make payments.