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Marlin GTX help

Point-of-sale and business management for tyre and mechanical workshops.

Credit Notes BT

Learn the basics about Credit Notes in Marlin GTX trusted automotive software by Megabus.

Updated 12 October 2026

**Marlin GTX** enables customer credits and invoice reversals to be processed using credit notes.

Credit notes can be added manually to apply adjustments, or automatically generated by reversing an existing invoice.

All credit notes can be processed using the Invoices module.

The module can be accessed by selecting Main > Data Entry > Invoices from the menu bar..

Adding Credit Notes

Credit notes can be added by clicking on the Credit Note button on the left.

In the Enter Credit Note window:

  • Select the Salesperson
  • Add products and values using the Line Details list
  • Click Finalise at the top

Reversing Invoices

Main > Data Entry > Invoices > Credit Note

Invoices can be reversed by loading the original invoice details into a credit note.

To reverse an invoice:

  • Select the Customer
  • Click the Invoice Reference picker

In the Select Invoice window:

  • Select the original invoice at the top
  • Review the Transaction Details below
  • Ensure the required line items are ticked
  • Click Select

The invoice details can be added to the credit note and the credit note can then be finalised as usual.

Tip

To insert the full credit amount into a payment type field, click the field and press Enter

For Further Details

See the Customer Credit Notes help guide.