In Netsuite Web Services, list fields require internal IDs to specify the list values.
First, you will need to enable the ‘Show Internal IDs’ in the system preference.
1. Go to Home > Set Preferences.
2. Under the General tab, under Defaults, check ‘Show Internal IDs.
After that, you can go to the list field configuration page, under the Values tab, you will see list of the values and their IDs.