Working example code that shows how to add an answer value from a custom registration form field to Event Espresso's [ESPRESSO_EVENT_ATTENDEES] template.

content-espresso_event_attendees.php

<?php
/**
 * Content Template for the [ESPRESSO_EVENT_ATTENDEES] shortcode
 *
 * Please be sure to change the Question ID on line 19 to match your custom Question ID
 *
 * Template Args that are available in this template
 * @type EE_Attendee $contact
 * @type EE_Event   $event
 * @type bool       $show_gravatar  whether to show gravatar or not.
 */
$custom_question_output = '';
if( $contact instanceof EE_Attendee ) {
	$prev_answer_value = EEM_Answer::instance()->get_var( 
			array(
				array(
					'Registration.ATT_ID' => $contact->ID(),
					'Registration.EVT_ID' => $event->ID(),
					 'QST_ID' => 107 // replace with custom question's ID
				),
				'order_by' => array(
					'ANS_ID' => 'DESC'
				),
				'limit' => 1
			),
			'ANS_value' );
	if( $prev_answer_value ) {
		$custom_question_output = ' &mdash; ' . $prev_answer_value;
	}
}	
if ( $show_gravatar ) {
	$gravatar = get_avatar( $contact->email(),
		(int) apply_filters( 'FHEE__loop-espresso_attendees-shortcode__template__avatar_size', 32 )
		);
} else {
	$gravatar = '';
}
?>
<?php do_action( 'AHEE__content-espresso_event_attendees__before', $contact, $show_gravatar ); ?>
<li><?php echo $gravatar . '&nbsp;' .  $contact->full_name() . $custom_question_output; ?></li>
<?php do_action( 'AHEE__content-espresso_event_attendees__after', $contact, $show_gravatar ); ?>

how can i use this code in my website? did i need to add it to "uploads/espresso/templates" ro edit other files?

@mafam1024
The recommended approach is you upload the template file into your WordPress child theme's directory.

SO I used the above code:

get_var( array( array( 'Registration.ATT_ID' => $contact->ID(), 'Registration.EVT_ID' => $event->ID(), 'QST_ID' => 12 // replace with custom question's ID ), 'order_by' => array( 'ANS_ID' => 'DESC' ), 'limit' => 1 ), 'ANS_value' ); if( $prev_answer_value ) { $custom_question_output = ' — ' . $prev_answer_value; } } if ( $show_gravatar ) { $gravatar = get_avatar( $contact->email(), (int) apply_filters( 'FHEE__loop-espresso_attendees-shortcode__template__avatar_size', 32 ) ); } else { $gravatar = ''; } ?>

full_name() . $custom_question_output; ?>

--- Is there a way to add a second field (Question ID = 11) and then sort them by the Question ID = 12?

Question ID 12 is their group name and the leadership of that group needs to know who in their group is registered and working through an entire list of 800+ registrations to find their members would be insane. I need them grouped. THANKS