##Introduction Invoice Ninja is a free and open source web-bases application software that can be used for invoicing, payments, time tracking and many more. It is best solution for invoicing and billing customers. You can easily create and send invoices online in seconds. Invoice Ninja allows you to create your own custom invoice and show live invoice as PDF file. In this tutorial, I will explain you how to install Invoice Ninja on CentOS 7 server. ##Prerequisites * A CentOS 7 x64 instance with......