Before uninstalling Twinmotion 2018, take care to deactivate your license to be able to reactivate it after.
You will find more information about deactivating a license here.
To begin the uninstalling, launch the uninstaller application installed with Twinmotion 2018.
A message appears asking you for the confirmation of your action. Click Yes.
Your Twinmotion 2018 is successfully removed. Click Finish to close the uninstaller.