It depends on company in which you want to get a job and type of industry. Most of the companies use their traditional approach for choosing product design software since most of the design features can be done by using same CAD software. But learn at least 2-3 CAD software so that you can get many opportunities. Completely learning even single CAD software is very difficult but learn completely the basic and essential features of 2-3 CAD software. Choose your area of interest of product design such as parts/shape design, sheet metal design, and surface design etc. Then learn the selected features completely.
Do I need to go for any CAD training classes?
Absolutely it’s not required. Good internet connection is more than sufficient to learn any software. There are thousands of free resources are available on the internet, you can utilize those resources efficiently but one small limitation is some companies are hiring depends on candidate’s extra value adding courses. Professional companies would never ask for any certification, they will only test your capability and knowledge in CAD software by giving some tasks.