How do I remove or disable notifications in QuickBook Desktop 2021

Thanks for getting in touch with the Community, jdrichardson. I appreciate your screenshot.

You can turn off popup messages for products and services from your Preferences window.

Here's how:
 

1. In the top menu bar, go to Edit, then Preferences.
2. Access your General tab, then My Preferences.
3. Turn on the Turn off popup messages for products and services option if it's turned off.
4. Select OK.

This should disable advertisements from displaying while using QuickBooks. There may still be some popups that show up even if you've already disabled them. You can close them manually if necessary. The one shown in your screenshot can be closed by clicking its Later option.

You can additionally submit feedback about these promotional notifications if you'd like to.

Please feel welcome to send a reply if there's any questions. Have an awesome Thursday!