This is really outside the scope of this plugin.
You should know that email is never secure, by nature. You have no idea who will read that email or if the email you're sending the data to is the correct email. Therefore, it is absolutely recommended that you do not send credit card details in an email or save them on your web server. Both are extremely unsafe and you can be held directly liable for any damages incurred to the card holder. Any server that stores credit card information must be PCI compliant and follow strict rules and regulations. It will be impossible for you to achieve that, I promise. That is why all websites use a payment gateway to accept payments. Nobody stores credit card information. I recommend that you research this subject more before you get yourself in trouble.