Welcome to the Community, @Ed Sr.
Let's configure your Apple mail to get your ability to send invoices back in QuickBooks Desktop (QBDT) for Mac.
To configure your Apple email, follow these steps:
- Open Apple Mail.
- Go to Mail, then select Preferences.
- Select General, then Apple Mail, beside the default email reader.
Once you're done, restart QuickBooks and then send your invoices.
In case the issue persists, you can perform the recommended troubleshooting steps in this article: Connect and track emails in QuickBooks Desktop for Mac.
Also, you may want to check out this guide as your reference to track your income and expense transactions in QBDT for Mac: User's Guide 2021.
Please feel free to leave a comment below if you have other concerns about managing invoices in QBDT for Mac. I'm always ready to help. Take care, @Ed Sr.