ChangeOrderOfAddressFieldsInCheckout

di.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="Magento\Checkout\Block\Checkout\LayoutProcessor">
        <plugin name="magevision_checkout_address_fields_order" type="MageVision\Blog33\Plugin\Checkout\Block\LayoutProcessor" />
    </type>
</config>

LayoutProcessor.php

<?php

namespace MageVision\Blog33\Plugin\Checkout\Block;

class LayoutProcessor {

  /**
   * Position the telephone field after address fields
   *
   * @param \Magento\Checkout\Block\Checkout\LayoutProcessor $subject
   * @param array $jsLayout
   *
   * @return array
   */
   public function afterProcess(
      \Magento\Checkout\Block\Checkout\LayoutProcessor $subject,
      array  $jsLayout
    ) {

       //Shipping Address
       $jsLayout['components']['checkout']['children']['steps']['children']['shipping-step']
       ['children']['shippingAddress']['children']['shipping-address-fieldset']
       ['children']['telephone']['sortOrder'] = 75;

      //Billing Address on payment method
       if (isset($jsLayout['components']['checkout']['children']['steps']['children']['billing-step']['children']
           ['payment']['children']['payments-list']['children']
       )) {
           $paymentList = $jsLayout['components']['checkout']['children']['steps']['children']['billing-step']['children']
           ['payment']['children']['payments-list']['children'];

           foreach ($paymentList as $key => $payment) {
               /* telephone */
               $jsLayout['components']['checkout']['children']['steps']['children']['billing-step']['children']
                   ['payment']['children']['payments-list']['children'][$key]['children']['form-fields']['children']
                   ['telephone']['sortOrder'] = 75;
               }
       }

       //Billing Address on payment page
       if (isset($jsLayout['components']['checkout']['children']['steps']['children']['billing-step']['children']
           ['payment']['children']['afterMethods']['children']
       )) {
           /* telephone */
           $jsLayout['components']['checkout']['children']['steps']['children']['billing-step']['children']
           ['payment']['children']['afterMethods']['children']['billing-address-form']['children']['form-fields']
           ['children']['telephone']['sortOrder'] = 75;

       }
    return $jsLayout;
  }
}