How do I add custom fields or meta-data to the PDF invoice templates?

In order to add custom fields or meta-data, use the below code to display meta-data. Replace {META_KEY} with the actual key. If you use another plugin, just ask the key from the author of that plugin.

<?php echo WPI()->templater()->get_meta( '{META_KEY}' ); ?><br>

Important: A custom template is required to add a custom field to the PDF invoice.

Please test the functionality on a development environment of your website. If it ceases to work, please revert back to the original state of your website and follow the tutorial again.