How to > Point 3D CoPilot > Menu options > Plane mode
  
Plane mode
The options for plane mode are UV, VW, WU.
1. Switch from 3D Pick mode to plane mode by clicking on an arc between two axes, or right-click and select the plane in the context menu. The arc disappears and the associated CoPilot arrows become green. The Point 3D CoPilot now has the same functionality as the 2D CoPilot.
2. Click points on your model or in the workplane.
3. The 3D Snapping option from the 2D CoPilot is available. Vertices and edges can be projected temporarily onto the active plane by hovering over these elements with the cursor. Feedback is drawn as a catchable element in the active plane. When the cursor approaches one of these catchable elements, the feedback snaps to that element. Click to use the position of that element as a 3D point.