Since e-mail is not secure, it would be safer to store the information server side and simply e-mail a message that a credit application has been saved.
There are a whole mess of factors here and while it is not that difficult to do what you initially invisioned, to make is "secure" is going to take a lot of work.
Here is a link to a thread that starts to answer your question, there are probably more:
Having a Form print instead of email
Hope that helps...