Email address taken from a drop down list


I would like to populate the email column with an email address linked to the applicant of an activity.
The applicant (guest in monday) fills out a form related to the board and the name of the applicant is in a drop-down list.
How can I do it?

I have a similar need and am interested in any responses you receive. Need ability to notify customer (which would be a guest in a monday board) using automations