This page will explain the Payment Required Sales Order/Invoice template.
On the Sales Order in the Payment Method, if you are using a method that has either Online Pre-Payment, Pre-Payment, or Payment on Sales Docs ticked. You can see what is ticked in the Payment Method Maintenance Screen.
The Order will be put on hold for Payment Required. This can be released before payment through the Orders on Hold screen.
The customer will receive an email stating that the order requires payment and attached will be the proforma.
Your customer would need to scan or click the QR code for it to open the payment screen, to enter the credit/debit card details.
Once they have done this, in the Sale order screen or Invoicing screen you are able to retrieve the payment details, the details will show in the Sales order - Payment Tab.
This will make the order has Invoiced and Paid.