At Invoice details page click on “Payment Button”. Then payment window will be open and you will be able to add the payment to that invoice. You can add Payment for multiple Invoices but all selected invoices must have same currency and customer.
You can add Amount for different Invoices separately. When you will press save it will make payment for multiple invoices according to added amount in particular invoices.
Credit Note Payment: In Payment Type list there is an option to use Credit Note Payment. If you want to make payment from Credit Note then payment should be selected as Credit Note. It will display Credit Note List of same currency and customer and you can select any one Credit Note from which you want to make payment. Total amount added in all invoices payments should not be greater than total available Credit Note Amount. The used amount will be deducted from available Credit Note amount. Add new Payment Type: While making a selection of Payment type you can also add new Payment type.