Notejoy for Mac
To uninstall the Notejoy app for Mac, you simply want to delete the Notejoy application from the Applications folder. To do this, open up Finder, which you should find on your Dock. Within Finder, you should see an Applications favorite on the left-hand sidebar. Click on that. You'll then see the full list of applications you currently have installed. Right-click on Notejoy and select Move to Trash.
Notejoy for WIndows
To uninstall the Notejoy app for WIndows, select the Start menu and then select Settings -> Apps -> Apps & features. Select Notejoy from the list of apps and then select Uninstall.