>Is there something I need to do in the Form to allow this with Acrobat Professional?
Yes. You need to enable the file to allow Reader users to save the form first.
Advanced>Enable usage rights in Adobe Reader...
Hmm. There seems to be no "Advanced" item in the current Adobe Reader. Nor its Preferences.
Are you talking about Acrobat, which does have an Advanced header item?
If so, how does this enable the form to be filled out, then returned and/or saved?
Setting up a form is very opaque to me.
It needs to be done in Acrobat.
Open the PDF in Acrobat and use Advanced>Enable usage rights in Adobe Reader.
That will give special rights to that particular PDF that will allow Reader users to fill it out and save it. Then they can attach it to an email and send it back.
One thing to keep in mind with this type of enabled form is that there is a limit to how many times it can be used.
You can either send it to 500 people and collect it from them an indefinite amount of times or you can send it to as many people as you want but can only collect data 500 times.
If you need to know more about that, I believe all of the text on that is in the Acrobat userlicense agreement, section 15.13.something.