bin/magento order:complete

class CompleteOrders extends \Symfony\Component\Console\Command\Command
{
    protected function execute(
        \Symfony\Component\Console\Input\InputInterface $input,
        \Symfony\Component\Console\Output\OutputInterface $output
    ) {
        $this->orderProcessorFactory->create()->completeOrders();
    }
}

class CompletePendingOrders
{
    public function execute()
    {
        $this->orderProcessor->addGreaterThanDaysFilter(7)->completeOrders();
    }
}

class OrderProcessor
{
    public function completeOrders()
    {
        $collection = $this->getCollection();
        .....

        while ($page <= $lastPage) {
            $collection->setCurPage($page)->load();

            foreach ($collection as $order) {
                try {
                    $this->invoiceCreator->execute($order);
                    $this->shipmentCreator->execute($order);
                } catch (\Exception $e) {
                    $this->logger->error($e);
                }
            }
            .....
        }

        return $this;
    }
}

class InvoiceCreator
{
    public function execute(\Magento\Sales\Model\Order $order)
    {
        .....
        $invoice = $this->invoiceManagement->prepareInvoice($order);
        $invoice->register();
        .....
    }
}

class InvoiceService implements InvoiceManagementInterface
{
    /**
     * Creates an invoice based on the order and quantities provided.
     */
    public function prepareInvoice(
        Order $order,
        array $orderItemsQtyToInvoice = []
    ): InvoiceInterface {
        $invoice = $this->orderConverter->toInvoice($order);
        .....
        $order->getInvoiceCollection()->addItem($invoice);

        return $invoice;
    }
}

class ShipmentFactory
{
    /**
     * Creates shipment instance with specified parameters.
     */
    public function create(\Magento\Sales\Model\Order $order, array $items = [], $tracks = null)
    {
        $shipment = $this->prepareItems($this->converter->toShipment($order), $order, $items);
        .....
        return $shipment;
    }
}