You do not need to any specific course to get a job into banking sector. You can directly apply for the clerical position in the banks by giving the entrance exam. The minimum academic criteria needed by various banks are 12th pass for getting job in the banking industry. And as you have completed 12th class, you are eligible to apply for Bank Clerk Jobs.

The selection procedure for these positions will be based on written exam and interview.

The written exam will consists of questions from the following categories:

Reasoning

Numerical ability

General Awareness

General English

Computer and Marketing knowledge

in order to qualify the written exam one needs to score minimum qualifying marks in each of these categories and remember one more thing there is ¼ negative marking for every wrong answer. 

Try to score good marks in this exam so that you will be having good scope to get a call for the Interview.

all the best