Converting Word files to PDF and making them fillable

I'm hoping you can help me help a small non-profit with this issue.  They have Word documents that need to be converted to PDF (which I found easy enough to do in Reader).  However, they need them to be fillable.  I think the only way to do so is to purchase Adobe Acrobat Pro.  They would like to send the forms to potential clients, have them fill them out and send them back.

My other question is do the potential clients need to have Adobe Acrobat Pro as well to fill in the form.  It seems like that would be a very expensive option for the clients.  I thought I read somewhere that Pro can extend rights to Reader to make the forms accessible to data, save and send back to the non-profit.  Any help would be appreciated.