User Help > Creating Custom Fields and Specifying Custom Field Values > What are Custom Field Values?
  
What are Custom Field Values?
When a project has custom fields defined on a project backing item, users can specify values for the custom fields. Changes made to custom field values are recorded on the item’s History tab.
Users with appropriate permissions to edit an instance of an item can modify custom field values using a Windchill RV&S GUI or the CLI. Custom field values are read-only in the Windchill RV&S Web interface.