// WordPress get all user emails
$args = array('orderby' => 'display_name');
$wp_user_query = new WP_User_Query($args);
$authors = $wp_user_query->get_results();
if (!empty($authors)) {
echo '<ul>';
foreach ($authors as $author) {
$author_info = get_userdata($author->ID);
echo '<li>' . $author_info->user_email . '</li>';
}
echo '</ul>';
} else {
echo 'No results';
}