To include custom field data in the notification email, here's the format:

First name: [[first_name]]

Last name: [[last_name]]

Full name: [[full_name]]

Message: [[custom_1]]

Reason: [[custom_2]]

[[custom_x]] where x is the number of the custom field.

You will find the number when you edit the custom field and URL will show the number:

Where x is the number in  [[custom_x]]