Hello.
For becoming an economic journalism you will have to complete your bachelor degree in journalism  from finance, economics, communication, after this you can go for master in the same or you can directly opt for the jobs, now for getting into this course of journalism there are various universities which offers this course and their admission criteria is different some takes admission on the basis of your class 12th merit and some takes admission on the basis of of their own entrance exam so find out with the college or university where you want to take admission.
Best of luck.