Business have many levels, but one thing is common to almost all of them. What we used to refer to as sliding along on a big mound of paper has now been replaced by modern electronics, but the concept is still the same. Because a business is subject to so many different rules, regulations, ordinances, taxes, etc. Someone, or several someones, is required to manage the myriad of elements that must be maintained just to keep the business open and legal. These are the folks that make sure the rent gets paid, the EOE information is on the wall, the bills are taken care of, the business complies with any applicable laws and local ordinances, that all of the employees get paid and have the necessary benefits, and all kinds of other stuff. If there wasn't a department to handle these tasks, the business would probably never get around to actually...um...doing business. As a result, they rely on the administrative people to ensure that they stay operational, and then they can turn their attention to clients, products, production, marketing strategies, whatever. In fact, if you ever want to know anything about the workings of a particular business, don't ask an officer of the company. Instead, ask an administrative person. They know more about what goes on than anyone else ever will.
