> For the complete documentation index, see [llms.txt](https://help.orderdesk.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.orderdesk.com/technical-documentation/templates-and-documents/how-to-build-custom-templates.md).

# How to Build Custom Templates

Order Desk uses a template language called Twig to build your email and receipt templates. Read about Twig [here](https://twig.symfony.com/doc/2.x).

The basic syntax uses two curly braces to echo a variable `{{ first_name }}` and a curly brace and percent to write PHP. You could do something like this:

```
{% if first_name is defined %} {{ first_name }} {% endif %}
```

Order Desk passes in order variables to each template. The best way to see what’s available is to review the existing code samples. You can also view the [Field Names Reference](/resources/order-desk-field-names.md) guide for assistance.

**TIP:**

Check out our sample [**VAT Receipt template**](/technical-documentation/templates-and-documents/vat-receipt-template.md) to see what a custom template looks like.

You’ll also find more sample templates by looking through our [**Technical Documentation guides here**](/technical-documentation/templates-and-documents.md).

### QR Codes and Barcodes

You can use Twig to add QR Codes and barcodes to your templates in Order Desk.

To create and work with QR codes and barcodes in Order Desk, please refer to the [How to Use Barcodes](/guided-walkthroughs/templates-emails-and-order-documents/how-to-use-barcodes.md) guide.


---

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