If this was a genuine question, the answer would be simple: "Don't even think about it". The security you need - both legally and to protect your bank from theft is significant, the legal requirements on banks as regards accountability and traceability is massive, and all this has be designed in from day one. That you don't even know where to start says that you are not even close to ready to do this in the real world, and would end up in jail for a very, very long time if you tried.
So this is a homework assignment instead.
While we are more than willing to help those that are stuck, that doesn't mean that we are here to do it all for you! We can't do all the work, you are either getting paid for this, or it's part of your grades and it wouldn't be at all fair for us to do it all for you.
So we need you to do the work, and we will help you when you get stuck. That doesn't mean we will give you a step by step solution you can hand in!
Start by explaining where you are at the moment, and what the next step in the process is. Then tell us what you have tried to get that next step working, and what happened when you did.
If you are having problems getting started at all, then this may help:
How to Write Code to Solve a Problem, A Beginner's Guide[
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I'll add this as well: Never store passwords in clear text - it is a major security risk. There is some information on how to do it here:
Password Storage: How to do it.[
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And remember: if this is web based and you have any European Union users then GDPR applies and that means you need to handle passwords as sensitive data and store them in a safe and secure manner. Text is neither of those and the fines can be .... um ... outstanding. In December 2018 a German company received a relatively low fine of €20,000 for just that.