How to create custom fields with this plugin?

how to create custom field with usernoice plugin.

You can use code structure like below.

add_action('un_feedback_form_body', 'un_feedback_custom_field_add', 10);
function un_feedback_custom_field_add(){
	?>
	<input type="text" name="abc" value="" id="?" maxlength="30" />
	<?php
}

add_action('un_feedback_created', 'un_feedback_custom_field_save', 10, 2);
function un_feedback_custom_field_save($id, $params){
	if( isset($params['abc']) ){
		update_post_meta($id, 'abc', $params['abc']);
	}
}