How to create invoice programmatically in magento 2

In article, we will learn how to create Invoice programmatically.

To Create Invoice of an order-

<?php

namespace Mageclues\Invoice\Controller;

class CreateInvoice extends Magento\Framework\App\Action\Action
{
    /**
     * @var \Magento\Sales\Api\OrderRepositoryInterface
     */
    protected $_orderRepository;

    /**
     * @var \Magento\Sales\Model\Service\InvoiceService
     */
    protected $_invoiceService;

    /**
     * @var \Magento\Framework\DB\Transaction
     */
    protected $_transaction;

    public function __construct(
        \Magento\Framework\App\Action\Context $context,
        \Magento\Sales\Api\OrderRepositoryInterface $orderRepository,
        \Magento\Sales\Model\Service\InvoiceService $invoiceService,
        \Magento\Framework\DB\Transaction $transaction
    ) {
        $this->_orderRepository = $orderRepository;
        $this->_invoiceService = $invoiceService;
        $this->_transaction = $transaction;
        parent::__construct($context);
    }
    /**
     * Marketplace order invoice controller.
     *
     * @return \Magento\Framework\View\Result\Page
     */
    public function execute()
    {
        $orderId = 100;
        $order = $this->_orderRepository->get($orderId);
        if($order->canInvoice()) {
            $invoice = $this->_invoiceService->prepareInvoice($order);
            $invoice->register();
            $invoice->save();
            $transactionSave = $this->_transaction->addObject(
                $invoice
            )->addObject(
                $invoice->getOrder()
            );
            $transactionSave->save();
            $this->invoiceSender->send($invoice);
            //send notification code
            $order->addStatusHistoryComment(
                __('Notified customer about invoice #%1.', $invoice->getId())
            )
            ->setIsCustomerNotified(true)
            ->save();
        }
    }
}

I hope this article is helpful for you. Please leave comment if you have any queries. Thanks!