Open Preview for me
In the Preview app
Use any of the following shape tools to select an area in an image and then crop, copy or delete:
Rectangular Selection
See
Draw a shape using a single stroke. Press your finger more firmly on the trackpad to draw with a heavier, darker line.
Note: Unlike the Sketch tool, the Draw tool doesn’t recognise standard shapes.
This tool appears only on computers with a Force Touch trackpad.
Shapes Take a picture of your screen in Preview on MacAnnotate a PDF in Preview on Mac