In Helper service, Driver will act as helper and will help in loading and unloading at ground floor.
You will see a tab of "Include Labor". Enable that and a new pop up will come where you can opt in this service.
No, currently the service is only limited to ground floor (up to 25m distance)
Yes, the price will get updated when you will opt this option. You can check the change in price at that time.
Update your app to the latest version. Then, you will be able to add 'Helper' serviceability.