Why can I not create one off service item to invoice without adding a saved product or service anymore?

QuickBooks requires a saved product or service item for each line to keep your sales tax and income reports accurate. This design also aims to provide a clearer picture of your revenue sources and prevent manual entry errors.

To help accommodate your unique billing requirements, consider adding a generic service item(Example: Miscellaneous Service or Custom Charge). When creating an invoice, select this item and modify the description and rate fields to reflect the specific details of the transaction and match your specific needs.

You're always welcome to post here if you have further questions.