Invoice: This indicates the purpose of the commercial document and should be placed near the top of the page. Name of your business: Format in bold and place at the top of the page. Include your company logo for a branded look. Seller contact information: This not only lets your customer know how to contact you if they have any questions about the invoice, but could also lead to future business; if they are happy with their experience working with you, they might use the information to contact you again or refer you to a friend.
While you can make up your own invoice or use a free template, it's often easier to use an invoicing system that offers more in depth features. Some invoice systems, like Harvest, offer the option to create estimates for big projects, keep track of multiple clients and send reminder emails when payments are late. Another option is Freshbooks, which offers similar features but includes profit and loss sheets, as well as trackers to help you manage your time. Both of these services can be used for free or upgraded for a small fee, and include lots of other cool features, like scanning receipts for work completed in the field.