Attaching a button with a link on an invoice for customers to review company is currently unavailable in QuickBooks Online. Let me take note of this idea and pass it along to the appropriate department and team members for consideration in future product updates.
A suggestion like this helps us determine what enhancements and improvements are needed to make our product more effective and convenient to use.
While we continue to make your experience with us even better, I recommend visiting our QuickBooks Online Blog to get the recent news, information about the latest features, and updates.
You're always welcome to come by the Community if you have additional concerns. It's my pleasure to help. Have a fantastic day!