System is sent8ng email form :quickbooks@notification.intuit.com How do I change the email to my email address

Hi there, @userbilling.

I'd be glad to help you change  the default email address to your business email address in QuickBooks Online. For now, the supported email is Gmail only. Other than that is not yet supported. You can use a Gmail address to send invoices to your customers. Here's how to change the default email address:

1. Create an invoice.
2. Once you're done, select Save and send.
3. Click the email ▼ dropdown above your customer's email address. I've included a screenshot for your additional reference.
   
   
   
   
4. Select Add Gmail address, then click Connect Google account.
5. Enter your email address and click Allow.
6. Input your password, then select Next.
7. Confirm the changes by clicking Allow.

Additionally, I added this handy reference about the frequently asked questions for managing Gmail address in QuickBooks: Send invoices from your Gmail address FAQ. 

I've included this article to help you with handling your customer's payments in the future: Record invoice payments in QuickBooks Online. This contains a detailed process from entering different kinds of invoice payments, such as partial payments and joint payments.

You're always welcome to post in the community if you have other questions or concerns. Tagging my name in the comment section works too. Take care and have a wonderful day.