Use the following steps to uninstall the app from your system:
Run the Uninstaller application to uninstall the Monotype Desktop App from your system. Default path for uninstaller is:
Windows: C:\Program Files(x86)\Monotype desktop app\uninstall.exe
Mac: /Applications/Monotype Fonts/uninstall.app
Wait for the uninstaller to complete the uninstallation process.
Check following folders after uninstallation:
Windows: C:\Program Files(x86)\Monotype Fonts
Mac: /Applications/Monotype Fonts/
If there are files remaining in these folders even after uninstallation is complete then manually delete the remaining files and restart your system.