custom_course_details.php

# add_filter('wplms_course_details_array','wplms_custom_course_details_information');
function wplms_custom_course_details_information($course_details){
  $course_details['custom']= array(
        'label'=>'custom',
        'callback'=> false,
      );
$course_details['custom1']= array(
        'label'=>'custom1',
        'callback'=> false,
      );
$course_details['custom2']= array(
        'label'=>'custom2',
        'callback'=> false,
      );
$course_details['custom3']= array(
        'label'=>'custom3',
        'callback'=> false,
      );
 return $course_details;
}

add_filter('wplms_course_details_widget','custom_info_course_widget',999999);
function custom_info_course_widget($course_details){
$course_details['custom'] = '<li>I am a custom Detail</li>'; 
$course_details['custom1'] = '<li>I am a custom Detail 1</li>'; 
$course_details['custom2'] = '<li>I am a custom Detail 2</li>'; 
$course_details['custom3'] = '<li>I am a custom Detail 3</li>'; 
return $course_details;
}