Instead of [tax_code] use [certificate_code] which is already available, your requirement for showing an unique number will be fulfilled
Then Go to wp-admin > Plugins > Editor > Select WPLMS Customizer Plugin and add this code there
add_shortcode(‘certificate_student_birth_place’,’certificate_student_birth_place’);
function certificate_student_birth_place( $atts, $content = null ) {
$user_id = $_GET[‘u’];
if(isset($user_id) && $user_id)
return bp_get_profile_field_data(‘field=Location&user_id=’.$user_id);
else
return ‘[certificate_student_birth_place]’;
}
This will be your shortcode for birthplace. This code fetches the value from Location Field and will show the text on your certificate when student earn this certificate
[certificate_student_birth_place]