In the second article of a four-part series on 'Building an Invoicing System', Leidago walks you through invoice management. If you are a freelance web developer, invoicing your clients for your paycheck at the end of each month, this application will help you manage your client details as well as your invoices, Leidago writes.

He began the previous article by creating a Login Script for a PHP Invoicing System. Leidago had an entire section devoted to 'What if I don't see that page?' where he explained if the page is not present it means that the extension has not been enabled or cannot be found. In which case you should go back to the PHP site and download a version that includes the source, unzip the package and copy the extensions directory to your PHP directory. Then you should open up the php ini file, find the line that says extension_dir and add the location of your PHP directory to the line. He also explained database schema and login program.

The second part by demonstrating invoice management in a PHP invoicing system. Leidago shows you how to finish the invoice page, and generate a table of all invoices in the database(allinv.php). He provides code for creating an invoice and also details how to create unpaid.php to list all unpaid invoices and to generate a new invoice.