Currently EE does not provide an option to include custom fields within the registration table, it could be done but would require custom development and likely the help of a developer.
If you are look looing for a developer familiar with EE we have some listed here:
The support post ‘Add additional columns to Event Espresso – Registrations’ is closed to new replies.
Have a question about this support post? Create a new support post in our support forums and include a link to this existing support post so we can help you.
Support forum for Event Espresso 3 and Event Espresso 4.