Customize the invoice number that the system generates for each invoice by configuring the Custom Invoice Numbering Format setting.
Troubleshoot and resolve issues with duplicated invoices for different dates.
Troubleshoot and resolve issues with the system generating duplicated invoices for the same date.
Troubleshoot and resolve 1062 Duplicate entry for key tblinvoices.PRIMARY errors.
Troubleshoot and resolve issues with multiple duplicate transactions occurring for the same service or invoice.
Enable proforma invoicing, which ensures sequential invoice numbers for paid invoices. Some countries' accounting practices require this.
The Invoices tab in General Settings allows you to configure how WHMCS generates and sends invoices and applies late fees.