Posting References
Posting References link financial fields to Tasks, Purchase Orders, and Stock for accounting integration. Fields cannot be added, but grouping names can be customized using Reference Groups.
Settings > Finance > Posting References
The link will open the Posting References grid. It is a grid view which can be searched, sorted and customised as normal.
To edit an existing Posting Reference click Edit 
. A pop up window will appear which will allow the creation or amendment of a Posting Reference.
Click to view - Posting Reference Fields and Descriptions
Complete the fields and click Save and Close 
.