1. If you use Odoo enterprise or online, simply activate the use of loyalty cards. No customization needed.

2. If you use Odoo community, loyalty cards feature is not available so you need customization. You can edit the pos.xml file and add following tag "<t t-esc='receipt.partner_id.name'/>" anywhere you want it.

3. As a soft alternative to point 3, just go to your Odoo point of sales settings, and add following code in the footer or header field:
   

   <!DOCTYPE QWEB>

   <t t-esc='receipt.partner_id.name'/>
   Odoo will interpret the content of the header/footer field and actually print the value of the variables you put in it. Note that it is visible only on printed receipt and not on the screen.

put this code in the header or the photer 

Hi @patrick, @Moustapha, I had the same error, did you manage to find a solution?

 Hi     @patrick  

I ve just tried the  3 option  because   it was  the easiest    since im not so good with coding 

but when i did   this  error  accured   

 Uncaught Error: QWeb2 - template['subreceipt']: Runtime Error: TypeError: Cannot read property 'name' of undefined

there is a template for that. find it and change it however you need.if not possible by default, add some code.

view: report_receipt