Lock and email PDF form

I've searched and found similar answers but not sure if they fit my scenario. I built a simple quote form in Acrobat Pro DC (2015.010.20060) for a client that he can customize for his clients and email to them using an email button. He uses Reader.  No problem, that works. I need to lock the fields after he finish his entries so that his client can not edit any of the fields. I suspect it is simple, but I am not familiar with scripting.