Editing a form that has been Prepared

I use the 'prepare form' function and previously, other people fill in free text using the 'fill and sign' function outside of the designated fields.  All of a sudden, the only area that can be edited are the fields I set while using the 'prepare form' function.  When I click 'fill and sign', i get an error stating "the author of this form has specified the fields which you can fill.  Click on any field to start filling form".  How can I change the setting to allow others to fill in more than just the field?