Programatically create an order in Magento 2.1

create.php

<?php
/**
 * @author    Godric Cao
 */
namespace Vendor\Namespace\Model\Subscription\Order;

class Create
{
    public function __construct(
        \Magento\Framework\App\Helper\Context $context,
        \Magento\Store\Model\StoreManagerInterface $storeManager,
        \Magento\Catalog\Model\ProductFactory $productFactory,
        \Magento\Quote\Model\QuoteManagement $quoteManagement,
        \Magento\Customer\Model\CustomerFactory $customerFactory,
        \Magento\Customer\Api\CustomerRepositoryInterface $customerRepository,
        \Magento\Sales\Model\Service\OrderService $orderService,
        \Magento\Quote\Api\CartRepositoryInterface $cartRepositoryInterface,
        \Magento\Quote\Api\CartManagementInterface $cartManagementInterface,
        \Magento\Quote\Model\Quote\Address\Rate $shippingRate
    ) {
        $this->_storeManager = $storeManager;
        $this->_productFactory = $productFactory;
        $this->quoteManagement = $quoteManagement;
        $this->customerFactory = $customerFactory;
        $this->customerRepository = $customerRepository;
        $this->orderService = $orderService;
        $this->cartRepositoryInterface = $cartRepositoryInterface;
        $this->cartManagementInterface = $cartManagementInterface;
        $this->shippingRate = $shippingRate;
    }

    /**
     * Create Order On Your Store
     *
     * Sample Test Data
     *
     *      $orderData=[
     *     'currency_id'  => 'USD',
     *     'email'        => 'test@webkul.com', //buyer email id
     *     'shipping_address' =>[
     *         'firstname'    => 'jhon', //address Details
     *         'lastname'     => 'Deo',
     *         'street' => 'xxxxx',
     *         'city' => 'xxxxx',
     *         'country_id' => 'IN',
     *         'region' => 'xxx',
     *         'postcode' => '43244',
     *         'telephone' => '52332',
     *         'fax' => '32423',
     *         'save_in_address_book' => 1
     *     ],
     *     'items'=> [ //array of product which order you want to create
     *         ['product_id'=>1,'qty'=>1],
     *         ['product_id'=>2,'qty'=>2]
     *     ]
     * ];
     *
     * @param array $orderData
     * @return int $orderId
     *
     */
    public function createOrder($orderData) {

        //init the store id and website id @todo pass from array
        $store = $this->_storeManager->getStore();
        $websiteId = $this->_storeManager->getStore()->getWebsiteId();

        //init the customer
        $customer=$this->customerFactory->create();
        $customer->setWebsiteId($websiteId);
        $customer->loadByEmail($orderData['email']);// load customet by email address

        //check the customer
        if(!$customer->getEntityId()){

            //If not avilable then create this customer
            $customer->setWebsiteId($websiteId)
                ->setStore($store)
                ->setFirstname($orderData['shipping_address']['firstname'])
                ->setLastname($orderData['shipping_address']['lastname'])
                ->setEmail($orderData['email'])
                ->setPassword($orderData['email']);

            $customer->save();
        }

        //init the quote
        $cart_id = $this->cartManagementInterface->createEmptyCart();
        $cart = $this->cartRepogitoryInterface->get($cart_id);

        $cart->setStore($store);

        // if you have already buyer id then you can load customer directly
        $customer= $this->customerRepository->getById($customer->getEntityId());
        $cart->setCurrency();
        $cart->assignCustomer($customer); //Assign quote to customer

        //add items in quote
        foreach($orderData['items'] as $item){
            $product = $this->_productFactory->create()->load($item['product_id']);
            $cart->addProduct(
                $product,
                intval($item['qty'])
            );
        }

        //Set Address to quote @todo add section in order data for seperate billing and handle it
        $cart->getBillingAddress()->addData($orderData['shipping_address']);
        $cart->getShippingAddress()->addData($orderData['shipping_address']);

        // Collect Rates and Set Shipping & Payment Method
        $this->shippingRate
            ->setCode('freeshipping_freeshipping')
            ->getPrice(1);

        $shippingAddress = $cart->getShippingAddress();

        //@todo set in order data
        $shippingAddress->setCollectShippingRates(true)
            ->collectShippingRates()
            ->setShippingMethod('flatrate_flatrate'); //shipping method
        $cart->getShippingAddress()->addShippingRate($this->rate);

        $cart->setPaymentMethod('checkmo'); //payment method

        //@todo insert a variable to affect the invetory
        $cart->setInventoryProcessed(false);

        // Set sales order payment
        $cart->getPayment()->importData(['method' => 'checkmo']);

        // Collect total and saeve
        $cart->collectTotals();

        // Submit the quote and create the order
        $cart->save();
        $cart = $this->cartRepogitoryInterface->get($cart->getId());
        $order_id = $this->cartManagementInterface->placeOrder($cart->getId());
        return $order_id;
}

It doesn't work for multiple order items. It takes only the last one from an array. But the calculation of quantity works properly.

Thanks, you saved my life.

It is only add one product bur quanity are multiple