Use this procedure step type when you want to create your own button for filing the data form. The reason you might do this is because you want perform other activities before filing the data form. For example, creating and filing another data form type related to to the current data form.
Warning:
If you create your own button for filing the data form then you should hide the original File button when the data form is opened for editing. Use the 'Set properties of a form element on a form' procedure step type.