Create ACF Admin menu Options Page & Sub Pages with Advanced Custom Fields

<?php
/**
 * Plugin Name: Techie Options
 * Plugin URI: https://github.com/yttechiepress/techie-options-page
 * Author: Techiepress
 * Author URI: https://github.com/yttechiepress/techie-options-page
 * Description: This plugin adds an ACF Options Page to WP.
 * Version: 0.1.0
 * License: GPL2
 * License URL: http://www.gnu.org/licenses/gpl-2.0.txt
 * text-domain: techie-options-page
*/

// Basic security.
defined( 'ABSPATH' ) or die( 'Unauthorized Access' );

if ( function_exists( 'acf_add_options_page' ) ) {

    // Add a top menu page
    acf_add_options_page(
        array(
            'page_title' => 'Footer Options Page',
            'menu_title' => 'Footer Options',
            'menu_slug'  => 'techie-options',
            'redirect'   => false,
            'capability' => 'administrator',
            'position'   => 5.4
        )
    );
    
    // Add a Sub Page
    acf_add_options_sub_page(
        array(
            'page_title' => 'Sub Footer Options Page',
            'menu_title' => 'Sub Footer Options',
            'parent_slug'  => 'techie-options',
        )
    );
}

// Save the ACF fields in the plugin.
if( function_exists('acf_add_local_field_group') ):
    acf_add_local_field_group(array(
        'key' => 'group_6119db99a4fb1',
        'title' => 'Footer Settings',
        'fields' => array(
            array(
                'key' => 'field_6119dba3720c0',
                'label' => 'Holding Company',
                'name' => 'holding_company',
                'type' => 'text',
                'instructions' => '',
                'required' => 0,
                'conditional_logic' => 0,
                'wrapper' => array(
                    'width' => '',
                    'class' => '',
                    'id' => '',
                ),
                'default_value' => '',
                'placeholder' => '',
                'prepend' => '',
                'append' => '',
                'maxlength' => '',
            ),
        ),
        'location' => array(
            array(
                array(
                    'param' => 'options_page',
                    'operator' => '==',
                    'value' => 'techie-options',
                ),
            ),
        ),
        'menu_order' => 0,
        'position' => 'normal',
        'style' => 'default',
        'label_placement' => 'top',
        'instruction_placement' => 'label',
        'hide_on_screen' => '',
        'active' => true,
        'description' => '',
    ));
endif;