How to delete or modify Payment receipts?

You can do this from the list of transactions, Payments received section, in the invoice or on the "Transactions" tab.

From the list of transactions

Go to the list of transactions. Click on the title:

And go to the page of Record payment creation:

In the opened sidebar, modify or delete the payment:

In the «Payments Received» section

You can delete several transactions at once in the Payments received section. Select the necessary ones and delete them.

In the invoice

Go to the invoice on Transactions tab and open the page of  Record Payment creation. Then edit it or delete it.