Mrthdrb

I have created extension attributes to order for rest API services. Also, I'm able to display the attributes on the order grid.

How can I display the same attributes on admin create order form and save it?

Here is my extension_attributes.xml file

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Api/etc/extension_attributes.xsd">
 <extension_attributes for="MagentoCheckoutApiDataShippingInformationInterface">
 <attribute code="delivery_day_slot" type="string"/>
 </extension_attributes>

 <extension_attributes for="MagentoSalesApiDataOrderInterface">
 <attribute code="delivery_day_slot" type="string"/>
 </extension_attributes>
</config>

And, I'm saving the data using plugin

<type name="MagentoCheckoutModelShippingInformationManagement">
 <plugin name="NM_save_delivery_slot_in_quote" type="<Namespace><ModuleName>PluginCheckoutModelShippingInformationManagement" sortOrder="1"/>
</type>

NamespaceModuleNamePluginCheckoutModelShippingInformationManagement

namespace <Namespace><ModuleName>PluginCheckoutModel;

class ShippingInformationManagement

 protected $quoteRepository;

 public function __construct(
 MagentoQuoteModelQuoteRepository $quoteRepository,
 MagentoCheckoutApiDataShippingInformationExtensionFactory $shpExtensionFactory,
 PsrLogLoggerInterface $logger
 ) 
 $this->quoteRepository = $quoteRepository;
 $this->shpExtensionFactory = $shpExtensionFactory;
 $this->logger = $logger;
 

 /**
 * @param MagentoCheckoutModelShippingInformationManagement $subject
 * @param $cartId
 * @param MagentoCheckoutApiDataShippingInformationInterface $addressInformation
 */
 public function beforeSaveAddressInformation(
 MagentoCheckoutModelShippingInformationManagement $subject,
 $cartId,
 MagentoCheckoutApiDataShippingInformationInterface $addressInformation
 ) 

 $extensionAttributes = $addressInformation->getExtensionAttributes();
 $shipExtension = $extensionAttributes ? $extensionAttributes : $this->shpExtensionFactory->create();

 $payload = file_get_contents("php://input");
 $attr = json_decode($payload, true);
 if(isset($attr["extension_attributes"]))
 $deliveryDaySlot = $attr["extension_attributes"]["delivery_day_slot"];

 $addressInformation->setDeliveryDaySlot($deliveryDaySlot);
 $quote = $this->quoteRepository->getActive($cartId);
 $quote->setDeliveryDaySlot($deliveryDaySlot);

 

 return;
 

Can any one please suggest a best approach?

Thanks in advance