Hi grandvalleyquail,
Welcome to Community! There currently isn't a way to upload a purchase order from an excel sheet to create an invoice, you can import bills and other data when necessary. If you would like to see this option available in future updates, please don't hesitate to submit a suggestion to the Development Team. You can also review third party apps, for the best fit for your business needs.
Feel free to reach out again, with other questions. We would be happy to help!
