Hi @jackie-burns9914,
For QuickBooks Self-Employed (QBSE), whenever you save an invoice as a draft with a line item that has incomplete info (in your case, lacking the per hour rate), then it won't be included in the draft.
You can input any number since it will be saved as a draft, then go back to edit the invoice and enter the correct values before sending it out.
You can learn of the new features available for invoices in this article: What's new with QuickBooks Self-Employed Invoicing?
Feel free to post a reply in the comments below, in case you have other questions in mind. I'll be sure to get back to you.