I want to be a software engineer so which subjects I have to choose?
A degree in computer science or software engineering is required to become a software engineer at UG level.
Also you should have subjects like computer science, physics, chemistry, maths in 12th. You can choose Bsc computer science or Bsc IT. A background in Maths can really help you out in this field.
Then get your skills in programming and yes you can go ahead with your field of interest.
Good Luck.