What are the steps to create a completion event with a link in the email that when clicked, 1) confirms the email is valid, 2) and the user who filled out the form is the person requesting the information?

Is this a question about Dynamic Forms?

You can use Regular Expression validation to force the user to enter an email address that has a valid form. If you need to verify that the email address actually works, you'll need to send an email and get the user respond. Verified registration in DotNetNuke is one approach.

I have no idea how to verify that the person filling out the form is the actual person, short of contacting them by phone or snail mail.