function wpf_sync_course_url( $user_id, $course_id, $access_list, $remove ) {

    if ( ! $remove ) {

        $update_data = array( 'ld_course_url' => get_the_permalink( $course_id ) );

        wp_fusion()->user->push_user_meta( $user_id, $update_data );

    }

}

add_action( 'learndash_update_course_access', 'wpf_sync_course_url', 10, 4 );

function add_course_url_field( $meta_fields ) {

    $meta_fields['ld_course_url'] = array(
        'label' => 'Course URL',
        'group' => 'learndash_progress',
    );

    return $meta_fields;

}

add_filter( 'wpf_meta_fields', 'add_course_url_field' );