Hi @Arun kumar Chin 

Out of the box (OOTB), it displays the name of the department. I wouldn’t recommend changing this behavior. Instead, consider adding another attribute to show the department ID as well, so that users can view both the name and ID in one place.

1. In the Attributes field, enter a comma-separated list of auto-complet attributes:

ref_auto_completer=AJAXTableCompleter,ref_ac_columns=first_name;last_name;email,ref_ac_columns_search=true

Replace the first_name with department_id or actual field name.

https://www.servicenow.com/docs/bundle/yokohama-servicenow-platform/page/product/service-catalog-man...