Hi Preeti,
To get a bank job, you will have to appear for entrance exams like IBPS PO, SBI PO, IBPS Clerk, etc. These exams are conducted at national level. Eligibility Criteria to appear for the exams is you must hold a Bachelor's Degree like B.A, B.Com, B.Sc, B.Tech or any other equivalent degree from recognised institute. Also, the candidate must be a Computer literate. They don't require any particular subject in graduation but if you are from commerce backgroud then it can be beneficial for you.

Hope this helps.
Good Luck!