Koha has the ability to define credits and debits in system administration. Credits and debits appear as options in patron accounts when charging fees and the Point of Sale module. The Koha Manual has instructions for setting up
Credits and
Debits.
How Do I Get Rid of a Credit or Debit Type We're No Longer Using?
Credit and debit types can be modified from Administration -> Credit types or Debit types.
Koha will not let you delete one of these accounting types, but you can archive them.
Archiving a credit or debit type will remove it from the dropdown for manual invoicing or credits on a patron's account. If it was archived by mistake, it can be restored.
This ability to archive credit or debit types only applies to credit and debit types added by a library for unique library-specific accounting types, like broken case replacement fees, Friends of the Library tote bags, credits for food bank donations, or summer reading fine vouchers to pay off fines. Debit types like lost fees or account creation fees are not eligible for archival since they are tied to specific system preferences and policies.
Credit Numbering System for Koha
Koha has a way to use a numbering system for a library’s credits. Each credit type created in Koha can be identified by an incremental number or not, and can be visible on the staff interface and printed on receipts.
Setup
In the Accounting tab for Patrons, a new column can be revealed for staff to see this Incremental Number. To have this credit number be visible, go to to the Administration Module > Table Settings. Locate the Patrons table, then under the Fines tab, uncheck the box for the Credit Number.
The system preference to turn on auto credit numbering is called AutoCreditNumber. This preference also controls how numbers are incremented. Similar to the autobarcode system preference, you can choose whether this number is incremented at 1 or includes details such as branch code or date.

Last step will be to identify the the Credit Types that the library would like to increment. This is a nice feature, as it allows libraries to pick and choose which credit types need this type of data or not.
To choose which credit types need this incrementing number information, go to the Admin module. Choose Credit types. A library can edit any existing Credit types and check mark the option to “Enable Credit Number”. A library can also create a new credit type and identify it this way also.
Patron Accounts
To see this in action, go to a Patron’s account. Choose to do a Manual credit on this patron’s account. Choose one of the credit types, that has been identified as “enabled credit number”. Once this credit has been applied to the patron’s account, staff will see this new column “ and the number that is now associated with this credit.
In the image below, a patron has been credited and the Credit Number generated was in the form of year followed by a number.
Notices and Slips
This number can be added to the receipts that Koha can create. To add this number to the receipt, this will be done in Notices and Slips.
Under Notices and Slips, the receipt is called, ACCOUNT_CREDIT. The line
[% credit.credit_number %]
Can be added to show this on the receipt.
Here is how that would appear when printed: