Which is the best software course for mechanical engineer for job purpose?
AutoCAD is the most popular software used my professionals with ME degree. If you are interested in pursuing your career as a Design Engineering, you can learn one of the design software like AutoCAD, CATIA, PTC Creo, SolidWorks, etc. In case you are interesting in analysis / simulation, you can go through some short courses in analysis software like Ansys, MoldFlow, Fluent, etc.
Good Luck.