how do I send a link to that user for their record so it can be edited by that user?

The next question is assuming that 500 people have filled in their forms. Each has their own password. Each has their own record.

If I create a record - how do I send a link to that user for their record so it can be edited by that user?

If I want to send a link so that their data can be viewed and not changed by someone else. How would I do this? I will also want the link for this to contain the password as above.

You can create autoresponder, and add the edit link to it:

So in this way the user will receive the link to to edit the form. Let us know if you have more questions.