Thanks for contacting us in the Community. The program offers a variety of features that make it easy for you to manage your work. I'll be happy to share more info and point you in the right direction so you can get the resolution you need.
I encourage you to check out the following article that shows you how to: Change your customer-facing email address. The article shows you how to change your customer-facing email address in just a few steps. Let me know how you make out as you browse through the article.
In case you need hands-on assistance I encourage you to contact our support team so they can assist you further. Here are our contact details:
Schedule a Callback or start a Chat: click(?) in the upper right in QuickBooks Online > enter "Contact support" > choose Contact Us > provide a brief summary > select Let's Talk > choose Get a callbackor Start a Chat.