Changing an email address in QuickBooks Online is just a few clicks. I'm happy to provide steps on how to accomplish the process.
If you're trying to change the company email address on your account, you can follow the steps below. By doing this, any updates from Intuit will send to this email, and the sales form email will automatically change.
Click on the Gear icon in the upper right-hand, then choose Account and Settings.
Select Company, then hit the Pencil icon beside Contactinfo.