This is a question we often get from midsize businesses with 15 or more users. Do you need a Windows Server in these days of cloud services? Some considerations are how many users you have, the types of services you want to run locally, and the platform you use online.
One example would be those that primarily use Office 365. They may not necessarily need a Windows Server in the office because everything can be controlled from the cloud. If you are a larger company with 100 or more users, you might need to have two servers that work parallel or are redundant to each other.
There is a benefit to running a local Windows Server with its user management tools. However, the Windows licensing and warranty are expensive. So you would want to weigh the benefits along with the costs and your budget. Your IT advisor or consultant can help determine the best way for you to manage and control the computers in your network.