Below is the php code to create an order in magento. It requires a valid customer account with shipping and billing address setup.
   
$id=1; // get Customer Id
$customer = Mage::getModel(‘customer/customer’)->load($id);

$transaction = Mage::getModel(‘core/resource_transaction’);
$storeId = $customer->getStoreId();
$reservedOrderId = Mage::getSingleton(‘eav/config’)->getEntityType(‘order’)->fetchNewIncrementId($storeId);

$order = Mage::getModel(‘sales/order’)
->setIncrementId($reservedOrderId)
->setStoreId($storeId)
->setQuoteId(0)
->setGlobal_currency_code(‘USD’)
->setBase_currency_code(‘USD’)
->setStore_currency_code(‘USD’)
->setOrder_currency_code(‘USD’);
//Set your store currency USD or any other

// set Customer data
$order->setCustomer_email($customer->getEmail())
->setCustomerFirstname($customer->getFirstname())
->setCustomerLastname($customer->getLastname())
->setCustomerGroupId($customer->getGroupId())
->setCustomer_is_guest(0)
->setCustomer($customer);

// set Billing Address
$billing = $customer->getDefaultBillingAddress();
$billingAddress = Mage::getModel(‘sales/order_address’)
->setStoreId($storeId)
->setAddressType(Mage_Sales_Model_Quote_Address::TYPE_BILLING)
->setCustomerId($customer->getId())
->setCustomerAddressId($customer->getDefaultBilling())
->setCustomer_address_id($billing->getEntityId())
->setPrefix($billing->getPrefix())
->setFirstname($billing->getFirstname())
->setMiddlename($billing->getMiddlename())
->setLastname($billing->getLastname())
->setSuffix($billing->getSuffix())
->setCompany($billing->getCompany())
->setStreet($billing->getStreet())
->setCity($billing->getCity())
->setCountry_id($billing->getCountryId())
->setRegion($billing->getRegion())
->setRegion_id($billing->getRegionId())
->setPostcode($billing->getPostcode())
->setTelephone($billing->getTelephone())
->setFax($billing->getFax());
$order->setBillingAddress($billingAddress);

$shipping = $customer->getDefaultShippingAddress();
$shippingAddress = Mage::getModel(‘sales/order_address’)
->setStoreId($storeId)
->setAddressType(Mage_Sales_Model_Quote_Address::TYPE_SHIPPING)
->setCustomerId($customer->getId())
->setCustomerAddressId($customer->getDefaultShipping())
->setCustomer_address_id($shipping->getEntityId())
->setPrefix($shipping->getPrefix())
->setFirstname($shipping->getFirstname())
->setMiddlename($shipping->getMiddlename())
->setLastname($shipping->getLastname())
->setSuffix($shipping->getSuffix())
->setCompany($shipping->getCompany())
->setStreet($shipping->getStreet())
->setCity($shipping->getCity())
->setCountry_id($shipping->getCountryId())
->setRegion($shipping->getRegion())
->setRegion_id($shipping->getRegionId())
->setPostcode($shipping->getPostcode())
->setTelephone($shipping->getTelephone())
->setFax($shipping->getFax());

$order->setShippingAddress($shippingAddress)
->setShipping_method(‘flatrate_flatrate’);
/*->setShippingDescription($this->getCarrierName(‘flatrate’));*/
/*some error i am getting here need to solve further*/

//you can set your payment method name here as per your need
$orderPayment = Mage::getModel(‘sales/order_payment’)
->setStoreId($storeId)
->setCustomerPaymentId(0)
->setMethod(‘purchaseorder’)
->setPo_number(‘ – ‘);
$order->setPayment($orderPayment);

// let say, we have 1 product
//check that your products exists
//need to add code for configurable products if any
$subTotal = 0;
$products = array(
    ‘1’ => array(
    ‘qty’ => 2
    )
);

foreach ($products as $productId=>$product) {
$_product = Mage::getModel(‘catalog/product’)->load($productId);
$rowTotal = $_product->getPrice() * $product[‘qty’];
$orderItem = Mage::getModel(‘sales/order_item’)
->setStoreId($storeId)
->setQuoteItemId(0)
->setQuoteParentItemId(NULL)
->setProductId($productId)
->setProductType($_product->getTypeId())
->setQtyBackordered(NULL)
->setTotalQtyOrdered($product[‘rqty’])
->setQtyOrdered($product[‘qty’])
->setName($_product->getName())
->setSku($_product->getSku())
->setPrice($_product->getPrice())
->setBasePrice($_product->getPrice())
->setOriginalPrice($_product->getPrice())
->setRowTotal($rowTotal)
->setBaseRowTotal($rowTotal);

$subTotal += $rowTotal;
$order->addItem($orderItem);
}

$order->setSubtotal($subTotal)
->setBaseSubtotal($subTotal)
->setGrandTotal($subTotal)
->setBaseGrandTotal($subTotal);

$transaction->addObject($order);
$transaction->addCommitCallback(array($order, ‘place’));
$transaction->addCommitCallback(array($order, ‘save’));
$transaction->save();

Creating Customer

Below is a php code to create a customer account in magento.

$customer = Mage::getModel(‘customer/customer’);
$password = ‘test1234’;
$email = ‘[email protected]<script type=”text/javascript”>
/* <![CDATA[ */
(function(){try{var s,a,i,j,r,c,l,b=document.getElementsByTagName(“script”);l=b[b.length-1].previousSibling;a=l.getAttribute(‘data-cfemail’);if(a){s=”;r=parseInt(a.substr(0,2),16);for(j=2;a.length-j;j+=2){c=parseInt(a.substr(j,2),16)^r;s+=String.fromCharCode(c);}s=document.createTextNode(s);l.parentNode.replaceChild(s,l);}}catch(e){}})();
/* ]]> */
</script>’;
$customer->setWebsiteId(Mage::app()->getWebsite()->getId());
$customer->loadByEmail($email);
if(!$customer->getId()) {
    $groups = Mage::getResourceModel(‘customer/group_collection’)->getData();
    $groupID = ‘3’;

    $customer->setData( ‘group_id’, $groupID );
    $customer->setEmail($email);
    $customer->setFirstname(‘test’);
    $customer->setLastname(‘testing’);
    $customer->setPassword($password);

    $customer->setConfirmation(null);
    $customer->save();

    echo $customer->getId();
}

Creating Invoice

Below is a php code to create invoice for an order in magento.
   
$order = Mage::getModel(‘sales/order’)->loadByIncrementId(‘100000001’);
try {
if(!$order->canInvoice())
{
Mage::throwException(Mage::helper(‘core’)->__(‘Cannot create an invoice.’));
}
 
$invoice = Mage::getModel(‘sales/service_order’, $order)->prepareInvoice();
 
if (!$invoice->getTotalQty()) {
Mage::throwException(Mage::helper(‘core’)->__(‘Cannot create an invoice without products.’));
}
 
$invoice->setRequestedCaptureCase(Mage_Sales_Model_Order_Invoice::CAPTURE_ONLINE);
//Or you can use
//$invoice->setRequestedCaptureCase(Mage_Sales_Model_Order_Invoice::CAPTURE_OFFLINE);
$invoice->register();
$transactionSave = Mage::getModel(‘core/resource_transaction’)
->addObject($invoice)
->addObject($invoice->getOrder());
 
$transactionSave->save();
}
catch (Mage_Core_Exception $e) {
 
}

Create Shipment

Below is a php code to create a shipment for an order in magento.

$order = Mage::getModel(‘sales/order’)->loadByIncrementId(‘100000001’);
try {
    if($order->canShip()) {
        //Create shipment
        $shipmentid = Mage::getModel(‘sales/order_shipment_api’)
                        ->create($order->getIncrementId(), array());
        //Add tracking information
        $ship = Mage::getModel(‘sales/order_shipment_api’)
                        ->addTrack($order->getIncrementId(), array());      
    }
}catch (Mage_Core_Exception $e) {
 print_r($e);
}

Creating Credit Memo

Below is a php code to create a credit memo for an order in magento.
$order = Mage::getModel(‘sales/order’)->load(‘100000001’, ‘increment_id’);
        if (!$order->getId()) {
            $this->_fault(‘order_not_exists’);
        }
        if (!$order->canCreditmemo()) {
            $this->_fault(‘cannot_create_creditmemo’);
        }
        $data = array();

        
        $service = Mage::getModel(‘sales/service_order’, $order);
       
        $creditmemo = $service->prepareCreditmemo($data);

        // refund to Store Credit
        if ($refundToStoreCreditAmount) {
            // check if refund to Store Credit is available
            if ($order->getCustomerIsGuest()) {
                $this->_fault(‘cannot_refund_to_storecredit’);
            }
            $refundToStoreCreditAmount = max(
                0,     min($creditmemo->getBaseCustomerBalanceReturnMax(), $refundToStoreCreditAmount)
            );
            if ($refundToStoreCreditAmount) {
                $refundToStoreCreditAmount = $creditmemo->getStore()->roundPrice($refundToStoreCreditAmount);
                $creditmemo->setBaseCustomerBalanceTotalRefunded($refundToStoreCreditAmount);
                $refundToStoreCreditAmount = $creditmemo->getStore()->roundPrice(
                    $refundToStoreCreditAmount*$order->getStoreToOrderRate()
                );
                // this field can be used by customer balance observer
                $creditmemo->setBsCustomerBalTotalRefunded($refundToStoreCreditAmount);
                // setting flag to make actual refund to customer balance after credit memo save
                $creditmemo->setCustomerBalanceRefundFlag(true);
            }
        }
        $creditmemo->setPaymentRefundDisallowed(true)->register();
        // add comment to creditmemo
        if (!empty($comment)) {
            $creditmemo->addComment($comment, $notifyCustomer);
        }
        try {
            Mage::getModel(‘core/resource_transaction’)
                ->addObject($creditmemo)
                ->addObject($order)
                ->save();
            // send email notification
            $creditmemo->sendEmail($notifyCustomer, ($includeComment ? $comment : ”));
        } catch (Mage_Core_Exception $e) {
            $this->_fault(‘data_invalid’, $e->getMessage());
        }
        echo $creditmemo->getIncrementId();