How to restrict a user from signing a form on Mobile App.

New Here ,

I created a form in Acrobat Pro DC (2015) and I don't want anyone to be able to lock it down with a signature. Acrobat Reader Mobile allows the user to sign anywhere on the document even when I have removed all of the signature fields. The form is reader extended, but I would only like to extend the filling of form fields, commenting, saving and printing functionality and not allow signing. Is this possible? Please help.