Pen

Pen builds a path one anchor at a time: click to place a corner point, drag while placing to pull a curve.

It is the tool for an outline that has to be exact, where Draw would be too loose and Shape too rigid.

The Pen is currently unreachable

On the version tested the Pen cannot be activated by either route.

Clicking Pen (P) in the rail leaves the previous tool highlighted, which is true of every tool button. And pressing P, which should be its shortcut, activates nothing — the previously active tool stays active.

So there is no way to select it, and this page describes what the tool is for rather than a workflow that can be followed today. Troubleshooting records the reproduction.

What to use instead

For a straight-edged outline, draw a rectangle with Shape, use Convert to Path in its properties, and move the anchors with Vector Tools.

For a rough shape, Draw it freehand and tidy the anchors afterwards.

For a precise curve, the drawing machines under Add elements produce mathematically exact curves from parameters, with Convert to editable path when you need anchors.

Related

Vector Tools is the anchor editor. Shape covers Convert to Path.