To add an invoice reference on the Case Card, head over to the Case Card, Details-view, under the Payer section.
Click on the Invoice Reference drop-down dialogue.
When you click on the drop-down dialogue, a list of client contacts will appear, select any client contacts you want to add as an invoice reference by clicking on the name.
For more information on how to add a Client Contact, click here.
Once you have selected an invoice reference, it will appear as below.
1. Ensure that you are either a Client Manager, a user with 'Assistant'-role, or 'Administrator'-right to be able to add an Invoice Reference.