I have used the feature prefix *21 because Telstra uses *21 to initialise their call forwarding. This will be common for many clients. Then select the purpose as “set call forwarding”. After this has been done press save.
To do the forwarding type *21 and add in the number you want to forward to. For example if I want to forward to my mobile 0400 000 000 ill dial *210400000000. Once you have dialled this you will hear a voice to say call forwarding enabled.
To cancel the function you will need to create a new feature. On your webpage click on features then feature codes