In most IT jobs, your work will ultimately help your employer to increase its profits. You don’t need to understand the financial details, but it’s good to know how your role will contribute to your organisation’s goals.
Companies whose main business is IT make money by providing IT products or services. This could involve selling hardware, selling licences to use software, or selling the services of technology experts. So you might help develop a product that gets sold, or help promote it to clients – or you yourself might be the ‘product’.
Companies whose main business is something else (eg finance or retail) use IT indirectly to help them make money, for example by making processes quicker, more efficient or less labour intensive.
In the public sector, many IT jobs also help indirectly by making processes quicker, more efficient or less labour intensive. In this case the aim is not to make money but rather to save taxpayers’ money, which pays for public services. However, other roles serve a different purpose, such as keeping the country safe from attack.