To force quit an unresponsive application, follow the steps outlined: 
 

On Windows devices, press Ctrl + Alt + Delete or Ctrl + Shift + Esc to open Task Manager. You can also right-click the task bar and select Task Manager. Select the unresponsive app and click End Task. Alternatively, you can press Alt + F4 to close the current window or application.
 

On Mac devices, press Command + Option + Esc to open the Force Quit menu, then select the unresponsive app and click Force Quit. If that doesn’t work, open Activity Monitor (Finder > Applications > Utilities) and close the app from there.

Tip: Uninstall applications that regularly cause your computer to freeze for improved stability.