If you're a company that plans to extend credit to your customers, you'll have to get familiar with invoice generation. The invoice is a bill to another business that lists the total amount due along with a breakdown of the items purchased. When it's time to generate invoices to send to your customers, you can make the process simpler by using templates in Microsoft Excel.
A professional header: The first item on your freelance invoice should be your business name, or your full name, in professional (and easy to read) font. The font size should be a little bigger than the rest of the text on the invoice, and possibly even bolded for emphasis. Next you'll want to include your contact information: your mailing address, phone number, email address, website, etc., right underneath your business name.