I appreciate you bringing your request forward here in the Community.
To see additional customization for invoicing within QuickBooks Online, I recommend leaving feedback for our Product Development Team. Your ideas and suggestions can be entered directly through your account by clicking the Gear icon in the top right corner, then select Feedback. This is the best way to ensure meaningful updates are added in the future.
I wish you and your business continued success. I'm here if you have any other questions.