Tax Configuration

WHMCS can gather necessary taxes when you make sales. First, you must enable tax support in WHMCS and configure the necessary settings.

Custom Fields

Custom fields collect additional information from or about your clients. You can set them as admin-only or make them visible to clients.

Customize Your Invoice Numbering

Customize the invoice number that the system generates for each invoice by configuring the Custom Invoice Numbering Format setting.

Enable Proforma Invoicing

Enable proforma invoicing, which ensures sequential invoice numbers for paid invoices. Some countries' accounting practices require this.


The Invoices tab allows you to configure how WHMCS generates and sends invoices and applies late fees.

Update Tax Rates

Update WHMCS's tax configuration when sales tax rates change. Make sure to do this as close to midnight or the system cron run as possible.