Lets face it; there is more than one invoicing app out in the world today. So, why Simply Invoice? Well, that’s Simple. Here at Simply Invoice we try and live by the idea that simple is the key. Your business is hard enough to manage without trying to keep track of a super complicated accounting systems. Simply Invoice allows you to create an estimate for a customer in seconds, then automatically converts it to an invoice once the work is complete. You can assign work to an employee and even manage what the employee has access to.