Howdy Manuela!
I would love to help you with this. Thanks for bearing with us, slightly longer responses over the holiday.
That is totally possible. It will require modifying the Email template to insert that info, and so a little bit of knowledge on modifying templates will be helpful. The first step is to familiarize yourself with the Themer’s Guide if you have not already. Now you will create an override for /event-tickets/src/views/tickets/email.php Within this file you will where it outputs the info for each ticket in the Tickets Email. Inside of this loop insert a call to tribe_get_custom_fields() to get the Additional fields data. Output the field you need, and you’re all set!
Does that all make sense? Will that work for you? Please let me know.
Cheers!
– Brook