Welcome to the QuickBooks Community, gigijo.
The ability to add or create blackout days isn't currently a feature in QB Workforce. Therefore, I suggest providing feedback so our engineers can potentially include it in future updates. You can do this in the QuickBooks Time interface.
- Log in to QuickBooks Time.
- Click the Help icon in the upper-right hand corner.
- Choose Suggest Idea.
If you have any other questions about using the Workforce app, please don't hesitate to go back to this thread. Take care and have a good one.