Card Form: embed card form doesn't have source code

Is there any option to pay for the source code of the card forms?

I'm not sure I understood your question correctly. You could get the source code of the card form in your Form builder, Publish>Embed>Source code.

Guide:How-to-get-the-Full-Source-Code-of-your-Form

If this does not answer your question,kindly give us more information so that we can assist you better.

Thank you.

This works for the regular forms, but not for the card forms. When will it be available for card forms? 

Thank you for the clarification, I have attached a feature request  to this thread. Although we cannot give you an ETA, rest assured your request has been forwarded to our developers..

Thank you.