Is crash course of fashion designing useful for making a good career and earn name and fame?

I suggest that at this stage you should focus on learning and have conceptual clarity about Fashion Design. You can then do specialised courses to grow in your field. You will earn name and fame by your work.

Crash course in nothing would give you good career, name or fame. By asking this you are questioning the intelligence of those who give their years to master an art. Design is a field that is age old and has been evolving every year like science. Again like science it pays to be at the cutting edge.