Hi
Is that part of the message that's being sent to them to confirm?
=> Yes, that's the email messages sent to user after he completed registration. However, you only need to enter this message if you require that each event has it own email message. If you leave this email message empty, the message in Configuration area will be used.
What's the difference between that and the thank you message?
=> That message is the email message sent to registrant email. The thank you message is the message displayed to user when he completed his registration
Offline mean the message used when users choose offline payment method for his registration.
Regards,
Tuan
