Slicer can read/write many file formats - see complete list here. You’ll have to use mesh converter to create a .step file from any of the supported file formats.
If you want this feature to be directly available in Slicer then you can implement VTK mesh to .step conversion using some library (and if you want the file format to be available in the Save data dialog then also add a custom node storage node).
can you elaborate in detail sir?
The updated link to the supported file formats is here: