Magento 2. How to send confirmation email for two emails at once?

Question

How to programmatically send an order confirmation email for two customer email addresses at once?

I created additional customer attribute for "contact email" field and need send confirmation to contact email and customer account email. How to it?

And I created Observer for sales_order_place_before event and wrote next code. But it's send only for contact email/customer account email. I need to send confirmation email to two emails at once.

<?php

declare(strict_types=1);

namespace Vendor\Module\Observer;

use Magento\Framework\Event\Observer;
use Magento\Framework\Event\ObserverInterface;
use Magento\Framework\App\RequestInterface;
use Magento\Sales\Model\Order\Email\Sender\OrderSender;
use Magento\Framework\Mail\Template\TransportBuilder;

/**
 * Class AfterOrderSave
 *
 * @package Vendor\Module\Observer
 */
class AfterOrderSave implements ObserverInterface
{
    /**
     * @var RequestInterface
     */
    protected $request;

    /**
     * @var OrderSender
     */
    protected $orderSender;

    /**
     * @var TransportBuilder
     */
    protected $transportBuilder;

    public function __construct(
        RequestInterface $request,
        OrderSender $orderSender,
        TransportBuilder $transportBuilder
    ) {
        $this->request = $request;
        $this->orderSender = $orderSender;
        $this->transportBuilder = $transportBuilder;
    }

    public function execute(Observer $observer)
    {
        $order = $observer->getEvent()->getOrder();

        $postParams = $this->request->getParams();
        $orderAccount = $postParams['order']['account'];
        $contactEmail = $orderAccount['id_contact_email'];
        $isContactEmailOnly = $orderAccount['id_contact_email_only'];

        if ($contactEmail && $isContactEmailOnly == true) {
            $this->transportBuilder->addTo($contactEmail);
        } else if ($contactEmail && $isContactEmailOnly == false) {
            $this->transportBuilder->addCc($contactEmail);
        }
    }
}

Answer 1

I did something similar with an extension

https://github.com/DominicWatts/EmailCC

Email is sent as CC

Hope that works for you. If not take a look at the source code and see how I did jt.