You can only do job in banks only after your graduation is complete.

For doing job in bank you have to appear in its entrance examination, some of them are SBI po/ clerk, RBI po, ibps po / clerk, hdfc po/ clerk.

Apart from this if you are in second years then you can always do sb internship in a bank. They will provide you a certificate along with some stipend depending onj the bank. For this you have to look at online job internships of bank or contact with bank manager or write an email to the bank.

The work which they generally assign to an intern is generally sort of research analysis as 8n the number of accounts opened , calculation of stats etc. They also look for students having some knowledge of economics and commerce.

All the best : )