The script load the Requester Name under Incident Additional field ( As a pick list), by choosing the requester name under additional field the script populates the user additional field value.

* Kindly create two additional fields under Admin -> Incident Additional Fields 

   Additional field 1 - To display Requester name 

   Additional field 2 - To display User additional field updated for selected requester. 

   User Additional field - Which holds the value that needs to be displayed under the request template. 

Below is the column name for additional field 1 and additional field 2 ( which needs to be updated under the script)

API Field name - User Additional Field 

* Navigate to Admin - > Incident Template -> Edit the template and configure the rule as shown below (Under Form Load).  Modify the additional field column name and user additional field api name under attached script and update it under FAFR as shown below.