This article covers:
How many custom fields can be displayed on the invoice?

How to display a Tax number custom field on the invoice?

Custom Fields can be created to track additional information about a customer or their subscription in addition to the default fields present in Chargebee. To create a custom field, head to Settings > Configure Chargebee > Custom Fields. Click Here for further details.

To display the custom field values on the customers’ invoice, navigate to Settings > Configure Chargebee > Invoices and Credit Notes and enable the Custom Fields toggle under the  Invoices tab. You can set up to three custom fields to be displayed on the invoice. 

A total of 3 custom fields will display on the invoice, at the top right corner.

When invoices are consolidated the custom fields will be displayed under each plan (Line Item).

Alternatively, if you prefer to display the EU & UK Customer’s VAT number on the invoice, refer to this link Tax line item not showing on the invoice for more information.

Related articles and documentation:

How do I create a Custom Field in my Chargebee account?
How to display custom fields to customers?