Next you'll want to include your contact information: your mailing address, phone number, email address, website, etc., right underneath your business name. If you'd like to up the professionalism, create and include your own logo on the right – or left-hand side of the header.
Accurate billing is extremely important when it comes to independent contractors and small business owners. You can't afford to lose a customer over something that should be done right the first time. Business owners who provide detailed, prompt invoices straight to the customer's inbox come out way ahead in the credibility stakes.