In a nutshell. No.

A former employer advised a client that the first email is secure it’s the subsequent emails such as replying isn’t. That is so not true email is NEVER SECURE. The client had a reservations form using a SSL to collect credit card information, but then that information was inserted into an email that went to the business. There are methods to securely collect credit card information for later manual processing.

Credit card or other sensitive information should never be sent using email. Absolutely not!

Okay, there are companies that offer secure email, but I still would never recommend using it for credit card or other sensitive information.