How to do volumetric segmentationin SLlicer 4.6.2?

The module “volumetric segmentation” is not present in Slicer 4.6.2 How to get it?

What do you mean by volumetric segmentation?
In Slicer, All segmentation (and visualization, processing, registration, etc) are done in 3D.

For segmentation I would suggest to use the Segment Editor module in the latest nightly version.