I am interested in getting into construction (builder) field what all courses can be done after 12th with commerce stream?

Hi, B.Arch Architecture or interior designing or Real Estate Management or Infrastructure Management or Construction Technology are some of the courses you may look into.

Since you are a commerce student, the best thing would be for you to join a construction business in accounts and learn the costing part of the business and along with that get an understanding of the business model. This will give you the desired confidence of starting your own business.