Master form vs. filled-out form

I am trying to create a master form which our salespeople can send out to customers to get them to fill out. But I don't want people to open the master form and fill it out, then save over top of the original. How do I protect my master form while continuing to use it to get form submissions? So, the master form is sort of like opening a template rather than the file itself. Then, when the form is saved, a different name is given to it. Any assistance understanding this better would be appreciated. Thanks