I can share some information on how to use the card reader with your QuickBooks Online (QBO), @MrFixitElectric.

You can only use or download the GoPayment app on your mobile device. 

If you use QBO in a web browser, you can send your customers an invoice that they can pay online. 

For more information on how to accept electronic payments for your invoices and sales receipts, see this article: Take and process payments in QuickBooks Online.

If you've got the card reader and downloaded the GoPayment app on your device, check this article on how to set it up and use it to process payments: Set up a card reader for QuickBooks GoPayment. 

In case you've encountered errors with the reader, here are some steps on how to fix it: Fix issues with the GoPayment and QuickBooks mobile app card reader. 

I'm always here if you need more help setting up or questions with your card reader. Let me know by leaving a reply below. Keep safe and have a great rest of the day!