Welcome to the QuickBooks Community, @IT_Admin.

Thanks for reaching out to us. I'm here to share some insight about emailing invoices in QuickBooks Online.

I've checked my tools, and I was able to confirm that there's an open investigation about being unable to directly send an invoice to your customer. As a recommendation, you can save the pdf of invoice and email it outside of QBO.

I also encourage you to subscribe to our callback feature. Our phone support team has tools to add you to the list of affected users so you can receive resolution updates via email. The notification list is the fastest way for us to update you on when a fix has been implemented.

Please follow these steps in providing your information:

1. Go to Help and click Contact us.
2. Type in phone support and click Continue.
3. Select the Get a callback tab and fill in the requested details.
4. Click the Call me tab.

And of course, you are more than welcome to visit the Community again if you have any other questions in the future. We'll be happy to answer them for you.