In ServiceNow, to include data from another table within a form, the Reference field type is utilized. A Reference field creates a relationship between the current table and another table by storing a reference to a record in the target table. This allows users to select a record from the referenced table and display related information seamlessly within the form.

A. Use the Date field type: This is incorrect. The Date field type is designed to store date values and does not facilitate referencing records from other tables.

B. Use the Phone Number field type: This is incorrect. The Phone Number field type is intended for storing phone number data and does not support referencing other table records.

C. Use the String field type: This is incorrect. The String field type stores text data and does not inherently provide functionality to reference records from other tables.

D. Use the Reference field type: This is correct. The Reference field type is specifically designed to create a link to a record in another table, enabling the incorporation of related data into the form.

For example, in the Incident table, the "Caller" field is a reference to the User [sys_user] table, allowing the selection of a user as the caller for the incident. This setup ensures data consistency and leverages existing records without data duplication.

For more detailed information, refer to the official ServiceNow documentation on Reference Fields.