An operating system is a user interface that helps control and manipulate computer functions. There are several different types, but their basic functions are all the same.

First of all, there is Windows—the most common user interface. It was the first user-friendly user interface created, and it was made by Bill Gates with Microsoft. It is the standard, and most computer applications are designed to run primarily through Windows, making it the most compatible system.

Apple or Macintosh operating systems are known for their ease of use and resilience against viruses or hacking. These are the sleekest and most streamlined, but you lose a lot of the customization and compatibility that comes with Windows. Many of the more niche and complex programs do not run properly on Macintosh, but the average user will find it the most attractive.

Macintosh is Linux based, and Linux is an open source platform that is constantly being reimagined by its many users in collaboration. It is the most flexible but certainly the most complex to maneuver since it requires considerable skill in programming.

An operating system is,

The software that supports a computer's basic functions, such as scheduling tasks, executing applications, and controlling peripherals.

Without operating systems, users would be required to interact with their computers according to complicated, cumbersome, and abstruse methods. Programs, which are how users execute tasks, require an operating system to live within and work. It is the top layer that we see when we use our phones, laptops, and tablets. Operating systems also manage the utilization of hardware resources, like memory. Some types are as follows:

• Graphical User Interface – A “GUI” uses graphics and icons to allow the user to interact with the system and are typically navigated by a mouse. Many operating systems use at least some graphical elements.
• Multiuser – This type of operating system can support more than one user on same computer at different times or at the same time.
• Multiprocessing – This type of operating system can support and use more than one computer processor at the same time.
• Multitasking – This type of operating system can support multiple software processes running at the same time.
• Multithreading – This type of operating system can support multiple parts of the same software program within the same process at the same time.

There are several types of operating systems, each with its own advantages.

To begin, the "operating system" is the set of interfaces and controls through which the user interacts with the computer.  Since we generally don't operate on a binary level, we need something that we can look at that makes sense to us so that we can actually use the computer.  Operating systems were created to make this easier.

The most common operating system in the world is Windows.  It has all kinds of versions.  In some ways its advantage is in its ubiquity.  If you are familiar with it, you can use the computers in almost any office in the world.  It is also considered more user-modifiable than the second system, Apple.

Though it used to be known as Macintosh, and now has names of animals like Leopard, calling it Apple will communicate what you are trying to say most of the time.  Some people consider it the most user friendly and the system that works the best "out of the box," though the user experience is more tightly controlled than in Windows.

A third and very interesting system is any open source operating system like Ubuntu.  These are infinitely user-modifiable and generally are grouped under the name "Linux."  These are entirely available to the public and are built on the premise that corporate entities controlling how people use their computers is inefficient and a bad idea so all the source code and applications are free and available to the public.