I'm here to help remove or change your registered email in QuickBooks Online (QBO).
Are you referring to your registered company email in QBO? If so, you can easily update this information by accessing the Settings. The process to do so is straightforward and won't take much time.
Here's how to do it:
In QBO, go to the Gear (Settings) icon at the top right.
Select Company Settings (or Account and Settings).
Tick Company from the left menu, then click the Pencil icon in the Contact info section to change your email address.
Enter the other necessary changes if needed.
Hit Save, then Done.
To know more about managing and changing company information in QBO, check out these articles for further guidance: