The work area (user interface) > Workplanes > Workplanes overview
  
Workplanes overview
Moving around in 3D space is an important part of the solid modeling process. Creo Elements/Direct Modeling provides workplanes to simplify this process. Workplanes allow you to work on any section of your part from any perspective.
A workplane is a transparent, infinite plane. You can think of a workplane as a sheet of glass positioned in 3D space. To help you visualize each workplane, Creo Elements/Direct Modeling displays a frame around it. Remember that the workplane is infinite, although the frame makes it look finite. You can create profiles on the workplane that overlap the frame. The frame will automatically resize to correspond to the size of your profiles.
You can place a workplane through your part, next to your part, or anywhere in 3D space. You can then create a profile on it and create a part or modify your part from that location.
To delete a workplane, click Delete 3D and select the workplane to be deleted.