Now that the cashier in my company has left, I want to be a cashier and secretary and ask my boss for a raise. Is it appropriate to talk to him?

Tellers also involve company secrets, so does secretarial work. Sometimes the two are kept secret. If you work part-time, knowing too much is a threat to the company. So, although your motivation is simple, the boss will worry that you may lose your present job. Besides, the cashier is not as idle as you think, even if the boss trusts you very much, there will be conflicts between the cashier and the secretarial work. So, what should you do first? Are very important jobs. I'm afraid you have to attend to one thing and lose another!