The article outlines the steps how to add non stock lines to a credit note.
FOLLOW STEPS BELOW:
1. Search and Open the Credit Note you would like to add a non-stock line to by clicking Search -> Credit Notes
2. Click the dollar sign icon to add a non-stock line to the credit note.
3. Select the non-stock type.
4. Enter the units, price and any other required fields.
5. Select a job product to link the non-stock item to.
6. Click 'Ok' to add the non-stock line
NB. For a quick tutorial watch below