I can certainly understand how a calendar feature could be useful and have submitted a suggestion about it as of today.
You can also submit your own feature requests while signed in.
Here's how:
Use the Gear (⚙️) icon, then go to Feedback.
Enter your suggestion(s) in the Have feedback? window.
If necessary, attach a file with your Camera (📷) icon.
Select Next.
Your feedback's definitely valuable to Intuit. It will be reviewed by our Product Development team and considered in future updates. You can stay up-to-date with the latest news about your product by reviewing Intuit's Product Updates webpage.
I'll be here to help if there's any questions. Have a lovely day!
What kind of business do you run? Consider having a scheduling app or a project management app to integrate with your QBO. Otherwise, utilize Google Calendar and a connector to integrate with QBO if you only need a simple need.