Hi,

You can simply create an Odoo custom module with an XML file. The structure of the module will be 

module_name

|── static

│ └── src

│ └── xml

│ └──OrderRecept.xml

├── __init__.py

└── __manifest__.py


And you can paste the below code to add the customer to the receipt screen.

<?xml version="1.0" encoding="UTF-8"?>
<templates id="template" xml:space="preserve">
   <t t-name="OrderReceiptScreenExtend" t-inherit="point_of_sale.OrderLinesReceipt" t-inherit-mode="extension" owl="1">
       <xpath expr="//t[@t-foreach='receipt.orderlines']" position="before">
           <t t-if="receipt.client">
               <div>
               <span>
                   Customer :
               </span>
                   <span class="pos-receipt-center-align">
                   <t t-esc="receipt.client.name"/>
               </span>
               </div>
               <br/>
           </t>
       </xpath>
   </t>
</templates>

And add this XML file to your manifest

'assets': {
   'web.assets_qweb': [
       'module_name/static/src/xml/file_name.xml',
   ]
}

After creating the custom module compress this module as a . Zip file.

Then go to the Odoo Apps menu. Enable debug mode, and on the top right side, you can see the import module tab. From there, you can select your module zip file. That's it.

Regards