Do you know how to put back who viewed my invoice...customer or myself?

I understand that you have some questions about emailing invoices in QuickBooks Online. I'll impart insight relating to this matter.

To clarify, currently, there is no option available to identify who viewed the invoice. However, if one of the receivers opens the emailed information from QuickBooks, you can check the status of the transaction. 

I appreciate your input about this feature and would like you to know that we are continually improving QuickBooks Online. Rest assured that this preference may be available in the future as we strive to provide the best possible experience for our users.

Also, I've attached some articles you can use to automatically send reminders to customers, as well as some additional information about emailing invoices:

• Automate invoice reminders in QuickBooks Online.
• Email or print multiple invoices and sales forms.

If you have any other questions or concerns, please don't hesitate to reach out to us. We're always here to help. Stay safe!