These forms are provided to the team via the workflow associated with the form. If it is the user's turn, he receives his tasks in his ToDo.
The workflow is the collection work steps.
Create a list of data items that are needed to be handled during the business case. We will create one ore more forms with the fields using these collected details. Maybe design and organize the fields on a peace of paper (as if we would use this).
digitalization: Forms show fields but may show and hide a selection of those from one step to the next. When you design the steps you will reorder and hide/show/edit fields as needed (even seperate those in different forms with split and join to allow parralel work done even sending webforms to involved outside parties). The automation to finalize the business case will be handled in one place.
A good workflow design never uses named persons it will always be designed using a conceptual role list of "organization units". So while you take interviews even create different "org units / roles" if those are occupied by a single person or N.N.. Think of sharing work later. You will just have to assign different or more people to a "org unit / role" named taskwise. These will be setup as an "Department".