Allow me to provide a few information about changing scheme colors in QuickBooks Online, jlg8440.

I can see the importance of being able to change colors so you can differentiate between companies. You'll want to check out our Customer Feedback page to see if a related request has already been submitted. If not, you can send feedback to let our product team know how this feature benefits your business needs.

Furthermore, QuickBooks gives you the tools to create attractive, professional-looking invoices, estimates, and sales receipts. Learn how to customize the appearance and layout of your sales forms. I've added this article for more details: Customize Invoices, Estimates, and Sales Receipts In QuickBooks Online.

Reach out to us if you have any questions about QuickBooks. We're here to get you covered.