The Display Name/Code on the item record prints in the Item column of sales forms such as Sales Order, Invoice and Packing Slip. If the user does not enter a Display Name/Code , the Item Name/Number appears on printed forms.
However, above behavior does not currently work on printed Picking Ticket forms. The Item Name/Number prints in the Item column on the Picking Ticket forms. This is a known NetSuite system limitation which is currently tracked under Enhancement 29164.
Possible Alternate Solutions are as follows:
1. Enter the Display Name/Code in the Sales Description field on the item records.
*The Sales Description information automatically populates on the Description column on sales orders. This option requires setting up the Picking Ticket form to print both Item and Description columns.
2. Setup a custom field as documented per Answer Id: 34567 - Ability to print both the Item Name and Display Name on the Picking Ticket using the Advanced PDF/HTML Template.