How to use the Knife Tool to cut a shape in Illustrator

First create a simple design or simple shape, like a above image. and i add 5 pt stoke to determine the cut is effective like a cut a bread.

Go to your selection tools > click the Knife tool but we are also have a Scissors tool and Erasers tool. To do this put the pointer arrow in the top of eraser tool and hold right click, drop to down to Knife tool and go to your design to create simple cut.

You can design different style using a knife tool, to create a circle, triangle and many more style, you can slice like a bread. to cut the shape click > knife tool and cut anything you want. Click Selection tool (V) twice, first click is to select a crop shape the second is to drop the shape.