Thanks for reverting @ShiellaGraceA 
I have classes being added to transactions already, but not payment transactions! From the attached image I can see you do not cater for adding classes to Payment transactions. Why?

My situation is that I use other software to generate invoices and take payments for those invoices.  (QB is my back office accounting solution)  My invoices post to QuickBooks immediately and I also pass in details of the classes that the invoices need to go to. I take payment for the invoices in this software too and at the end of day, I run a Cash Reconciliation procedure, to 'push' the payments to QuickBooks. The payments will match up with the respective invoices.

My issue is that payments for the invoices, which are in different classes, are required to be posted to different bank accounts (Cash , Credit Card, PayPal, AmazonPay, eBay, etc). 
All Payment transactions debit my Cash Clearing account but I have no way of seeing which class the payment relates to when I run a quick report for this account, as the payment doesn't record a class.

Is there a way the class from the invoice posting could be utilized? 

Kind regards
Denis