Open the Start menu and go to Power>Restart.If you have a Windows 10 update that is stuck downloading or installing, the first thing you should do is restart your system. There are still many kinks that need to be worked out.
An update may start to download and get stuck, it may show it is downloading but never move beyond 0%, it may download and start to install but get stuck in the middle, or at 0%. Windows Updates still run into problems and these problems can be distributed to any part of the installation process. Some updates will download and install while your system is running while others will require a restart.
Windows 10 gets several scheduled update every month there is normally a cumulative update, antivirus definition update, security patches, and more.