How can I create Magento invoice programmatically
You need to load Magento order first and then use “prepareInvoice” method to create Magento invoice
$orderid = 1;
$order = Mage::getModel("sales/order")->load($orderid )；
if($order->canInvoice()){
$invoice = Mage::getModel('sales/service_order', $order)->prepareInvoice();
if($invoice->getTotalQty()){
$invoice->setRequestedCaptureCase(Mage_Sales_Model_Order_Invoice::CAPTURE_OFFLINE);
$invoice->register();
$transactionSave = Mage::getModel('core/resource_transaction')->addObject($invoice)->addObject($invoice->getOrder());
$transactionSave->save();
}
}