This article covers:
The fields that can be displayed on an invoice. 

Can the invoice fields be changed after an invoice is generated?

The fields displayed on an invoice are of two types

 - the invoice line items that are automatically added to the invoice based on the subscription details

- the additional information about the customer(address, VAT number, custom fields) and the subscription(invoice notes, custom fields) that you can choose to display on the invoice

You can customize the invoice fields based on your requirement. The invoice customization settings are available under Settings > Configure Chargebee > Customize Invoice & Credit Notes. Refer to this solution article for the list of customization options available for the invoices.

However, note that it is not possible to modify an invoice once it is generated. This is because the invoice includes payment and tax-related details and which cannot be modified after being generated. 

If you have further questions regarding this, please feel free to reach out to support@chargebee.com.