Enable Proforma Invoicing

Some accounting practices, particularly for EU-based companies, require you to use sequential invoice numbers for paid invoices. In most cases, you must also enable proforma invoicing.

You cannot enable Enable Proforma Invoicing without enabling Sequential Paid Invoice Numbering.

Enable Sequential Invoicing

To enable sequential invoicing:

1. Go to your tax configuration settings.

Go to Configuration () > System Settings > Tax Configuration.

2. Enable tax support.

In the General Settings tab, enable Tax Support.

3. Update your VAT settings.

In the VAT Settings tab:

Enable Proforma Invoicing/Sequential Paid Invoice Numbering.
For Sequential Invoice Number Format, specify the format you want to use for numbering. You can also include letters (for example, include your company’s initials and the year to differentiate invoices for each year to create WHMCS2007-{NUMBER}). WHMCS replaces {NUMBER} placeholder with that invoice’s number.
Update the value for Next Paid Invoice Number. This allows you to set the next number to assign to an invoice.
- Each time a customer pays an invoice, the number increases by 1.
- You may want to alter the number here if, for example, you remove an invoice or at the beginning of a new year, to start at 1 again.

4. Configure when WHMCS resets invoice numbering.

If desired, update the value for Auto Reset Numbering. This determines when WHMCS will automatically reset Next Paid Invoice Number to use for newly-paid invoices.

You can set this to Never, Monthly, or Annually.

5. Enable invoice due date changes.

If desired, enable Set Invoice Date on Payment to set the invoice date to the current date.

6. Save your changes.

Click Save Changes.