Katamaze Documentation

Tips and tricks of Billing Extension

In this page you can find a list of tips and tricks that you can use in your WHMCS in conjunction with our Billing Extension module.


WHMCS uses auto-tags to let you customize the Sequential Invoice Number Format. You can configure them in Setup > General Settings > Invoices > Sequential Invoice Number Format. In a standard installation of WHMCS you can use the following auto-tags:

  • {YEAR}
  • {MONTH}
  • {DAY}
  • {NUMBER} This is the invoice number

Billing Extension allows you to use additional auto-tags that are not available in WHMCS:

  • {USERID}

It means that you can customize the Sequential Invoice Number Format to something like this:



This feature is very useful in case you need to store all your PDF files of invoices with a particular name in your Document Management System.

Quantity shortcut

With the use of a particular syntax in the description of an invoice item, you can display quantity and unit price as you can see from the screenshot below. The syntax is [quantity:X] where the X represents your quantity (e.g. [quantity:10]). The module will then automatically handle and show the unit price and quantity on your invoice.


Show customized text on Invoices and proformas

This is not an hidden feature of the module but just an hint. Let's say that you need to display two particular messages on your PDF invoices:

  • Show on all proformas "This is not a VAT invoice"
  • Show on all paid invoices "To be used as VAT invoice"

Simply open your invoicepdf.tpl files located in templates/{YOUR_TEMPLATE} directory and place the following code where you want to show the above messages:


if($status=='Paid'): $pdf->Cell(180,4,"To be used as VAT invoice",'','','C');
else: $pdf->Cell(180,4,"This is not a VAT invoice",'','','C'); 


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