Creating a professional freelance invoice is vital to the success of your business. If you sent your client paper receipts and scribbled notes, they would not be as likely to pay you on time and would probably question the you run your business.
Use a digital format – Using a digital format is one way to ensure your invoice is professional, and to indicate that you're likely to use the latest tools, and follow best practices, on the job. Simple mobile apps like Invoice2go will allow you to create and send professional estimates and invoices on site when the project is still fresh in your client's mind. These apps can even store receipts so you have a real-time way to keep your expenses organized for easy presentation to your clients.