Good day, @danghramm.
Let me help you ease your task in QuickBooks Online (QBO).
You can manually add your customer's email to their profile. That way, their email info will automatically populate when creating an invoice. Let me show you how:
- Go to Sales and select Customers.
- Click the name of the customer, then select Edit.
- Under the Email field, add their email address.
- Select Save.
Additionally, I've got these helpful resources to guide you further on how to:
Loop me in if you have other concerns about customizing fields in QBO, I'd be glad to assist you. Take care!