Can I add a separate billing email address, to receive the invoices on one and all other communication from intuit on another email address?

Hello there, @daniel52.

At this time, the option to add a separate billing address is unavailable in QuickBooks Online.

As a workaround, you can edit the billing address on the customer's profile. Here's how:

1. Go to the Sales tab and select Customers.
2. Select the customer you need to edit the billing address.
3. Click on Edit.
4. On the pop-up, make the necessary changes. Then, Save.

I've got some article that might help you with sending invoices and estimates in QuickBooks Online (QBO):

• Send an invoice.
• How to Send Estimates, Quotes, & Proposals.

Know that I'm here to help if there's anything else you need. Thanks for coming, and have a good one!