Submissions Element Field Type
The Freeform Submissions field type by itself is not the most usable feature, but when paired with the Relations feature it allows Freeform to do extraordinary things like become a tool that let's your users comment on entries, submit ratings and reviews for Commerce (and regular) products and more! The Relations feature essentially allows you to feed another Craft Element ID to the form that is attached to the submission(s), and the Freeform submission then becomes attached to the other element the same way an Asset does, etc.
Creating the Field
Creating a Freeform Submissions field is done just like any other fieldtype, here's an overview of the process:
Go to the Settings area in Craft control panel. Click on Fields.
Click the New field button in the top right corner.
Name the field as you wish. For example: Related Submissions with a handle of relatedSubmissions.
For the Field Type option, select Freeform Submissions from the list.
Selection Label is the text that will appear on the button which opens the Freeform Submissions selection pop-up dialog.
Click the Save button in the top right corner to save the new field.
Your Freeform Submissions field is now available to be assigned to other sections.
How it Works
Please see the Relating Submissions to Elements documentation for a complete guide on setting this up.