Clip by Line
The clip by line tool allows you to cut a polygon by drawing a line across it where you want the cut to be.
Shortcut:CTRL + P
To use the Clip by Line tool, follow the steps outlined below:
Click the Open Transformations button on the Mapping tab.
Select the polygon to clip
Select the Clip by Line tool
Draw a line across the polygon where you want the cut to be.
Double left click to finish drawing.
Click Save