Corporation can do the business in a different way from an individual or partnerships. They can issue shares to the general public and raise the money. They can invest that money in the business and improve it. When they are in profits they can buy back the shares and increase their share. The corporations can even take over another business with proper bidding.
Managing a corporation is a typical process and it need legal support. You need to communicate with the stake holders and share holders to take any important decision. This is a time taking and costly process. As a corporation you need to pay the tax for the profits that the company got. When this money is distributed to share holders as dividends, they again need to pay tax on that money to the government.
The job of a financial manager is to take care of the money flow in the corporate business. He need to collect the money flow from the investors to the company. He shall manage and use that money in a proper way and get the profits. This extra money shall be again distributed to the share holders and to the people or entities who invested in the business. Thus he plays a crucial role in establishing the corporation as a good entity. The job of the finance manager is to provide confidence in the investor that they run under certain principles. He shall check any project before taking it for the business. If he believes that the project can give profits he can start thinking about funding the project.