CannonVoice is a versatile tool for creating and sending invoices effortlessly. It offers an open-source platform that is developer-friendly, allowing for easy integration with IFTT or CRM systems. Its markdown function allows for customization of invoice templates. What sets it apart is the ability to send visually appealing PDFs through email using its user-friendly interface. Alternatively, emails can be sent through its API system. This software is perfect for freelance contractors who need to send concise invoices through email with ease.