Yes, @dcolliver, you can determine which email address QuickBooks uses when sending out reminders for automated payment. Allow me to show you how.
To start, QuickBooks uses the default email address, quickbooks@notification.intuit.com, when sending reminders, however if the your customer replies to that reminders it will sent to your company email used in QuickBooks.
Here's how to confirm:
- Log in to your QuickBooks Online account to your web browser.
- Go to Sales menu.
- Select Invoices tab.
- Choose the drop-down menu next to Receive Payment for any customer.
- Click Send Reminder.
You will see the email used for sending a reminder.

Currently, QuickBooks Online (QBO) does not have a specific feature to verify whether your customers are receiving reminders. However, you can check the status of an invoice to determine if it has been sent and whether your customer has viewed it.
Here's how:
- Go to Sales menu.
- Select Invoices tab.
- Select a customer who has a status of "sent."
- You can Viewed status indicating how many times the invoice has been viewed by your customer.

Additionally, I'll leave this article for your future use if you want to learn how to print invoices and sales receipts: Email or print multiple sales forms.
Before we wrap up, I recommend checking out our QuickBooks Live Expert Assisted. Their dedicated bookkeeper can bring your past books up to date and manage your bookkeeping for you from start to finish.
Don't hesitate to return to this thread if you have more questions about automated payment reminders in QBO or any QuickBooks-related issues. Have a great day!