Iphone 4s problem.enter password for exchange account?

This poped up and i don't know the password what the hell does this mean it keeps poping up

Contact the person who set up your e-mail on your phone. They would know. Clearly, you are not the person who set up your phone since you are asking this question.

You need to talk to your IT department, or possibly a parent/family member if they set it up.