What are the Custom form fields Short codes

This issue is a major issue which would not make me encouraged to buy this plugin.
I created new custom filed in the booking form. I cannot find any documentations on how to use these fields in email notifications. Only yhr bsic shows up but not the newly created.

Free version is typically the door to pro version one one is satisfied with the plugin. This app was recommended to me by a friend but it seesm I am not able to get straight answers for my questions.

Custom fields created under settings-Checkout-Checkout Form Fields, after creating them, how to send thier content in email notification. Typically you use short codes such as [NAME], [DATE], etc.
What to use for custom fields, how to use input in custom fields in email notifications.

Thanks