Thank you for sharing your concerns with the Community,melindakogut. QuickBooks Self Employed mostly helps you separate your personal and business expenses, manage your taxes, send and track simple invoices, sync with Intuit Turbo tax, and track mileage.
In contrast, QuickBooks Online only offers the ability to create purchase orders and so much more. You can sign up for this service to set up Purchase Orders. For additional information about this, you can refer to this article.
Please let me know if you have any other questions. The Community and I will be here to assist you with your needs at any time. Continue to be safe and take care.