How to Enable Reader users to save form data (READER EXTEND):
Ordinarily, Reader users cant save filled-in copies of forms that they complete. However, you can extend rights to Reader users so they have the ability to do so. These extended rights also include the ability to add comments, use the Typewriter tool, and digitally sign the PDF.
FROM ACROBAT PRO
Open a single PDF, or select one or more PDFs in a PDF Portfolio.
Choose Advanced > Extend Features In Adobe Reader.
These extended privileges are limited to the current PDF. When you create a different PDF form, you must perform this task again if you want to enable Reader users to save their own filled-in copies of that PDF.