Hi,
there are two products to enable additional rights to a form.
Adobe Acrobat and Adobe LiveCycle Reader Extensions (LC RE).
Here's an article by Niall which descibes the things.
http://assuredynamics.com/index.php/2010/11/using-livecycle-forms-in-acrobat-and-reader/
You will need Acrobat to enable saving of the forms to your clients. LC ES is generally not an option, because of it's pricing!