In a task report, you can add a column for "Task >> Category Name". This will place a link to a popup with the form in the report.
In a project report, you add "Project >> Category Name" for the same thing.
Caveat: Don't use "Category >> Name" as it will not give you the popup.
If you want to auto-add a form to an object, create a column for one of the fields on the form. When that field is filled out inline (on the report), the form will be added to the object.
Caveat: the chosen field can only exist on the one form you want auto-added, so Workfront knows what form you're referring to.