All three are different styles of computer operating systems. Windows is the most popular with the best compatability with the major software producers and the most user friendly. The downside is that Windows is a major target for Malware and Viruses. Apple Macintosh would be the next most popular. It is built of off the Unix OS and has more resistance to Malware and viruses due to different security protocols. The downsides are that not all major softwares are compatible and, often times, the users must be self taught. Linux is it's own OS and is the least popular of the three. While Apple and Windows have a wide variety of support if problems occur, Linux is usually self diagnosed and repaired. It's users are almost always self taught. Linux is the most resistent to viruses and Malware due to strict security procols and the fact that it isn't very popular.
The only answer is to try them all out somehow and you'll know the difference or just google it. The latter might save you some frustration though.
1. Windows - Advantages: Most software, most types of software, operating system you can expect to see on computers at most jobs, OS very simple (made for people that know nothing about computers and do not care to learn anything either). Disadvantages: As it is the most common OS in the world it is the OS targeted by 99% plus thieves, hackers, ..., Microsoft thinks they own your system and determines what you should name things and where they should go, Microsoft controls your a large part of your security, Microsoft with updates keeps turning automatic updating on (why I will not migrate to Windows 10), old programs seldom work on newer versions of operating systems or require major configuration to make work.
2. Mac - Advantages: BACKWARD compatibility (If you have program you like and want to keep using it, OS upgrades do not prevent it), fair amount of software most of which is well written and tested, Apple respects the computer is yours, relatively simple to use but not as simple as Windows. Disadvantages: COST of computer and peripherals, updates are harder than with Windows.
3. Linux Advantages: For the person that wants to work close to the computer it is the best, most user control, excellent full featured OS. Disadvantages: Not intuitive at all, requires you to KNOW Linux, updating is a pain, generally poor or slow driver support for peripherals, starting to become popular enough that hackers are starting to target it, most games written for Windows based operating systems do not work on Linux systems. Most games on Linux systems are at about the level of Donkey Kong (original) for graphics unless you buy/subscribe to something like wine (software to try to allow game coded calls to Windows DirectX subroutines to work on Linux systems).