To Change Payment Type / Record Payment for invoice you need to add Payment Reciept, Please Follow the steps below to create Payment Reciept :

Step 1 : Go to Payment Reciept Menu & select Inward Payment from Sub Menu.

Step 2 : Click on “Add New” To add new Payment Reciept

Step 3 : On Add Payment Reciept page Fill the Details as show,

1 – Select Customer for which you are Adding payment Reciept
2 – Select Payment date from List
3 – Select payment options
On Account (Payment Will be added to Customers Account for all Unpaid invoices )
On Invoice (You have to select unpaid invoices to add payment from the list of invoices )
4 – If you Select On Invoice it will show a List of all Unpaid Invoices, You have to select Invoice From it to record payment
from Current Transaction (Select Invoice will show in Green Part)
5 – Select Payment type Cheque/Cash from List
6 – Enter Amount for this payment Transaction
7 – Enter Payment Note then Save ( Optional )