This question is like going to a doctor and asking, “Which is the best medicine?” or going to a restaurant and asking “Which is the best dish?”. The course you do after 12th standard depends on your interests. If you have interest in science, engineering, technology, and medicine, choose a career like medicine, pharma, engineering, space sciences, architecture, etc. If your interest is in humanities like history, economics, sociology, etc choose a career in these subjects. All careers will give high salaries provided you are good at that subject and can apply that knowledge to solve real world problems. One of the purpose of education is to solve problems – education for the sake of it is not the end goal.
See what subjects you like, and then search for a career in those fields. Dont search for the most paying career because you may not have the aptitude to study the subjects that are necessary for that subject.
All the best for your career.