How do you do a forced quit on a Mac?

There are two ways:

1. You go to the Apple menu (little Apple in upper left corner) and select "Force Quit" then choose the applications you want to force quit in the "Force Quit Applications" window. Press Return, Press "Force Quit."

2. Press "Option+Command+Esc" to open the "Force Quit Applications" widow. Select the application you want to quit. Press Return, Press "Force Quit."

If you mean "Forced Shutdown" of the computer, press the power button for 5 seconds.