The file presents several Simple Invoice Templates. They are all similar. Take the first template as an example. In general, an invoice would mainly include four parts, the information about the company, the information about the clients and the most important part of the details of the transaction and the payment information as well. This template is created based on these elements. The difference is that this template shows the information in a very detailed way. If you don't mind the length of your invoice, this template would be a good reference.