There are times when the taskbar refuses to hide when a fullscreen app is launched. While the taskbar remains visible for all the applications and programs open on the system, Windows automatically hides it when an app is launched which requires full-screen mode, for example, when you open Youtube in fullscreen mode, run a video player like VLC player or start playing a video game. The taskbar is usually located at the bottom of the Windows 10 display where you can see the currently open apps along with the system tray which gives information like battery usage, sound icon, network icon, calendar etc.