The main difference between the identity code and the barcode is that the first is generated automatically upon task creation/import while the barcode is created manually by the user.

Identity or tracking code can be found in Tasks ⇒ Task Profile ⇒ Tracking Codes.

The barcode can be found/added in Tasks ⇒ Task Profile ⇒ Product Code / Barcode.

Alternatively, it can also be added in the CSV file if the tasks are being imported, under the column productCode.