What does the pen tool in photoshop do?

Answer 1

Do you mean Clone Stamp Tool? With this tool you can clone part of image. With C,one Stamp Tool selected, Alt + click to define source for cloning then paint with brush over area where you want to clone source you have defined.

Answer 2

With Pen Tool you can draw vector object (shape) or path which can be converted to shape, vector mask or selection.
The pen tool creates Paths that can be converted into shape layers or selections.

Answer 3

By clicking on start and where you want to be end point.On second and every next click you can make line to be Curve,by dragging points on ends of line

Answer 4

To write or draw something on a photo or design

Answer 5

the tool has many uses but you should start here at the related link I have put in.