When the user wants to print the vendor name associated to the item in the Item Fulfillment:
- Go to Setup > Customization > Transaction Column Fields > New
- Create a Free-form Text Field
- Under Applies to Select the checkbox Item Fulfillment and Print on Packing Slip
- Under Sourcing and Filtering, select the Source List as Item and Source From as Vendor
- Click on Save
After creating this field make sure that in the packing slip print, under columns the newly created field is selected.