You can add another email to a customer’s profile by separating them with a comma, Sean.
In your QuickBooks Online account, navigate to My Apps and select Customers under the Customer Hub dropdown. Then, follow these steps:
- In the Customers page, find and click on the specific customer to open their profile.
- From there, click on Edit and input the email addresses, separating them by a comma and a space.
- After completing this step, select Save to confirm the changes.

Once completed, your customer will receive notifications at both email addresses whenever sales transactions are sent.
Please feel free to reach out on this thread if you have any further questions or need additional assistance. We’ll be around to help.