Voucher classes for Credit Notes are similar to sales invoices except for one important inclusion. You can set the class for interest entries to enable adjustment of interest payable. If the Interest option is selected, the other sales invoice-like options will not be available. A separate class may to be created for entries like Sales Returns. Since Sales and Purchase Invoice classes have already been dealt with, we shall not elaborate on this behavior anymore.
Debit Note classes can be set for interest entries only. Classes for other entries are not available as the invoice mode of entry is not possible for Debit Notes.