I appreciate you taking the time to visit the Community, sdwire.
For now, you can only send invoices from your Gmail address. I suggest sending feedback to let our product developers know of your request. This might be included in the future. To do that, sign in to your QuickBooks Online account and go to the Gear > Feedback.
You can always visit our QuickBooks Blog to stay updated with the latest news and feature releases. I'm also adding this article for more information about the feature: Send invoices from your Gmail address FAQ.
You're always welcome to get back here if you have any suggestions or other concerns with QuickBooks Online. Have a great day!