The default Magento 2 displays the address information, payment, and shipping information, etc. on the admin sales order view.
However, sometimes it may not be enough based on the business requirements.
Therefore, one needs to add custom block in admin sales order view in Magento 2.
For example, you are offering customized products and the customers add instructions for their personalization. To display those instruction texts in the admin sales order view, you can use the below solution.
Also Read: Add a Row Count to The Order Sales View Items Table in Magento 2.4
Or, if you are an Indian store, you may display GST information in the sales order view.
Display any custom block based on your business requirements as shown in the below figure:

Steps to add custom block to admin sales order view in Magento 2:
1. Create registration.php file at app\code\Vendor\Module directory
<?php use \Magento\Framework\Component\ComponentRegistrar; ComponentRegistrar::register(ComponentRegistrar::MODULE, 'Vendor_Module', __DIR__);
2. Create module.xml file at app\code\Vendor\Module\etc directory
<?xml version="1.0"?> <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd"> <module name="Vendor_Module" setup_version="1.0.0"/> </config>
3. Create sales_order_view.xml file at app\code\Vendor\Module\view\adminhtml\layout
<?xml version="1.0"?> <page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" layout="admin-2columns-left" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd"> <body> <!--add custom block --> <referenceBlock name="order_additional_info"> <block class="Vendor\Module\Block\Adminhtml\Order\View\View" name="custom_view" template="order/view/view.phtml"/> </referenceBlock> </body> </page>
4. Create block file View.php in Vendor\Module\Block\Adminhtml\Order\View
<?php namespace Vendor\Module\Block\Adminhtml\Order\View; class View extends \Magento\Backend\Block\Template { public function myFunction() { //your code return "Customers' Instruction"; } }
5. Create view.phtml in Vendor\Module\view\adminhtml\templates\order\view
<div> <h1><?php echo $block->myFunction()?></h1> <h3>I want two different sizes, i.e., M and XL for the customized tshirts ordered here. Also, I want to increase the font size of the text to 25.</h3></br> <h3>Thank you.</h3> </div>
That’s it.
You can also add a custom Phtml in Magento 2 admin to change the complete layout.
Also, do share the solution with the Magento Community via social media.
Thank you.