The copy invoice feature appears to be broken. Looks like a new feature called "Get Signature" was added to invoices and that may have broken the duplicate feature

Thank you for notifying us of the issue you are experiencing, @sallred8. We understand how runtime issues can disrupt your business activities within the program. We're here to share an update about this matter.

We have an ongoing investigation about this one that our engineering team is still working on a fix. The issue is not related to the Get Signature feature. Rest assured that our engineers are aware of this matter and are diligently working on a fix so you can get back to business seamlessly.

You can contact our Customer Support Team to have your name added to the list of affected users and ensure that you receive email updates about the investigation's progress and get notified as soon as it's resolved. You can request that they add your name to the list of individuals affected. Then, provide this investigation number for easy tracking: INV-97895.

Here's how: 

1. Click the Help (?) icon.
2. On the Assistant tab, enter Talk to a human.
3. Enter a short description of your concern and press Enter.
4. Select Contact Us to connect with a live support agent.
5. Choose how you'll want to get in touch with the support.

• Start a chat with a support expert.
• Get a callback from the next available expert.

Please ensure to review their support hours to know when agents are available. This way, you can contact them at a time that is convenient for you.

You can also create customized, expert-looking invoices, estimates, and sales receipts with the help of QuickBooks. Scan this article for complete guidelines: Customize invoices, estimates, and sales receipts in QuickBooks Online. 

I apologize for any inconvenience this has caused you, and I appreciate your patience while we work toward resolving this issue. In the meantime, if you have any other questions or concerns with managing invoices, please don't hesitate to let me know. I'm here to assist you in any way I can.