In Vicidial, when you create custom fields in a List, you are actually building a custom "Form" with those fields in it. This becomes a new tab available for the agents in addition to the standard client data tab and the Script tab. The campaign can be configured to show this new Custom Form by default for the agent ... which sounds an awful lot like an "additional form feature" to me. but try to avoid using "OSDial" on this forum as that software is so obsolete people may ignore you. LOL
Custom fields must be activated in system settings, and then your user must have "Custom fields modify" activated to allow you to see/create custom field entries and menus.
It is an excellent feature and has matured quite well. Solidly implanted in the system now and thoroughly tested.
happy hunting.