I have created a satisfaction survey for my clients. However, I do not want just anyone to be able to access this. Is it possible to lock people out of the survey? Example, is there a way where a client must enter their email address to access the survey? 

If so, please let me know how to do it. If you have another suggestion, as in a passcode to access the survey, I am open to ideas.

I don't want just anyone to take this survey.

Thanks!