Edit order items; Add new items to order;

editorderaddproduct.php

<?php
/**
 * Copyright © MageWorx. All rights reserved.
 * See LICENSE.txt for license details.
 */
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
ini_set('memory_limit', '5G');
error_reporting(E_ALL);

use Magento\Framework\App\Bootstrap;
use Magento\Framework\Exception\NoSuchEntityException;

require 'app/bootstrap.php';

// Code
$bootstrap = Bootstrap::create(BP, $_SERVER);

$objectManager = $bootstrap->getObjectManager();

/** @var \Magento\Framework\App\State $state */
$state = $objectManager->get('Magento\Framework\App\State');
try {
    // Set STATE to adminhtml to imitate admin side actions
    $state->setAreaCode(\Magento\Framework\App\Area::AREA_ADMINHTML);
} catch (Exception $exception) {
    echo $exception->getMessage();
}

$orderId = 1205;//1195;

/** @var \MageWorx\OrderEditor\Model\Order\OrderRepository $mwOrderRepository */
$mwOrderRepository = $objectManager->get('MageWorx\OrderEditor\Model\Order\OrderRepository');
/** @var \MageWorx\OrderEditor\Model\Edit\Quote $mwQuoteProcessor */
$mwQuoteProcessor = $objectManager->create('MageWorx\OrderEditor\Model\Edit\Quote');

/** @var \MageWorx\OrderEditor\Model\Order $order */
try {
    $order = $mwOrderRepository->getById($orderId);
} catch (NoSuchEntityException $noSuchEntityException) {
    echo __('No such order with id %1', $orderId);
}

/* Items to add  */
$items = [
    /* product id */
    2252 => [
        /* requested item params (buyRequest) */
        'qty' => 1
    ]
];

try {
    $orderItems = $mwQuoteProcessor->createNewOrderItems($items, $order);
} catch (Exception $e) {
    echo __('Unable to add items to the quote, error: %1', $e->getMessage());
}
/*
 * Example request from magento admin:
 * q prefix is for newly added items (q - quote)
 * another items - regular items in order (existing items)
 * the "action" field could be used if you wish to remove an item.
form_key: 8N11LLf4Q6Se5YwR
order_id: 1204
block_id: order_items
item[1796][item_id]: 1796
item[1796][item_type]: order
item[1796][product_id]: 2259
item[1796][discount_tax_compensation_amount]: 0.00
item[1796][weee_tax_applied_row_amount]: 0.00
item[1796][price]: 50.50
item[1796][price_incl_tax]: 50.50
item[1796][fact_qty]: 1
item[1796][subtotal]: 50.50
item[1796][subtotal_incl_tax]: 50.50
item[1796][tax_amount]: 0.00
item[1796][tax_percent]: 0.00
item[1796][discount_amount]: 0.00
item[1796][discount_percent]: 0.00
item[1796][row_total]: 50.50
item[1796][action]:
item[1796][back_to_stock]: 1
item[1797][item_id]: 1797
item[1797][item_type]: order
item[1797][product_id]: 2258
item[1797][discount_tax_compensation_amount]: 0.00
item[1797][weee_tax_applied_row_amount]: 0.00
item[1797][price]: 49.50
item[1797][price_incl_tax]: 49.50
item[1797][fact_qty]: 1
item[1797][subtotal]: 49.50
item[1797][subtotal_incl_tax]: 49.50
item[1797][tax_amount]: 0.00
item[1797][tax_percent]: 0.00
item[1797][discount_amount]: 0.00
item[1797][discount_percent]: 0.00
item[1797][row_total]: 49.50
item[1797][action]:
item[1797][back_to_stock]: 1
item[q3011][item_id]: 3011
item[q3011][item_type]: quote
item[q3011][product_id]: 2253
item[q3011][discount_tax_compensation_amount]: 0.00
item[q3011][weee_tax_applied_row_amount]: 0.00
item[q3011][price]: 1.00
item[q3011][price_incl_tax]: 1.00
item[q3011][fact_qty]: 1
item[q3011][subtotal]: 1.00
item[q3011][subtotal_incl_tax]: 1.00
item[q3011][tax_amount]: 0.00
item[q3011][tax_percent]: 0.00
item[q3011][discount_amount]: 0.00
item[q3011][discount_percent]: 0.00
item[q3011][row_total]: 1.00
item[q3011][action]:
 */

$requestItems = [];
foreach ($orderItems as $item) {
    $requestItems['q' . $item->getId()] = [
        'item_id' => $item->getId(),
        'item_type' => 'quote',
        'product_id' => $item->getProductId(),
        'discount_tax_compensation_amount' => $item->getData('discount_tax_compensation_amount'),
        'weee_tax_applied_row_amount' => $item->getData('weee_tax_applied_row_amount'),
        'price' => $item->getData('price'),
        'price_incl_tax' => $item->getData('price_incl_tax'),
        'fact_qty' => $item->getQtyOrdered(),
        'subtotal' => $item->getData('subtotal'),
        'subtotal_incl_tax' => $item->getData('subtotal_incl_tax'),
        'tax_amount' => $item->getData('tax_amount'),
        'tax_percent' => $item->getData('tax_percent'),
        'discount_amount' => $item->getData('discount_amount'),
        'discount_percent' => $item->getData('discount_percent'),
        'row_total' => $item->getData('row_total'),
        'action' => $item->getData('action'),
    ];
}

$params = [
    'order_id' => $orderId,
    'item'     => $requestItems
];


try {
    $order->editItems($params);
} catch (Exception $e) {
    echo $e->getMessage();
    echo $e->getTraceAsString();
}

echo __('Success!');