How do I update payment without tax for single invoice?

Go to ‘Manage invoice’ >> ‘Invoice action’ >> ‘Update invoice payments’
The list of invoices that you have created will be displayed
The last column enables you to choose the particular invoice
Click on ‘Update payment’ option
That particular invoice opens up
In the ‘Enter payment’ section you can enter the amount that you received in the ‘Enter amount paid’ tab
Click on ‘Enter payment’ and the payment that you received will be successfully updated