Computer software is a grouping of computer programs that tell a computer how to perform.  In other words, it tells the computer what to do.  If you have a program that is written to perform mathematical calculations, the software will tell the computer how to calculate the figures.  The difference between computer software and computer hardware is that the hardware is the actual physical components of a computer that you can actually touch.  The software is what the hardware uses to perform functions and cannot be touched.
There are many different types of software available.  End user software is where there is a person versus another computer or application on the other end.  System software is referencing the operating system that the computer uses which helps to monitor its resources.  Testing software is an automated program that may mimic a user or other application to ensure it is functioning as designed.     There is also software required to operate your keyboard, mouse, printer and any other external device you may have.
There are two different types of monitoring software.  There is the type of monitoring software that is used to monitor other computer applications.  This software will identify potential problems before they occur or provide alerts to a command center that will notify them of an incident or problem that has occurred and needs to be fixed.  The other type of monitoring software can be used by employers to monitor their employee’s activities on their computers.   This is to ensure the employee is making proper use of their time while working as well as ensuring the employees are not accessing or attempting to access applications they should not be accessing.  Some people refer to this as spyware as it typically is running without the employee knowing. 
Many types of software are available as a download on the internet for free; sometimes referred to as shareware.  These free downloads can be very useful to programmers as this allows them to utilize something that is already in existence rather than having to create a new program.  The reason this software is made available for free is to assist a programmer in utilizing another piece of hardware or software.  The creator of this hardware and software is generally who has provided the free software download.  Without it, the programmer may switch to some other program that does not require an additional download.
Computer software is behind almost everything you do on a daily basis anymore.  From setting your thermostat in your house to your desired temperature, turning on your water in the morning for a shower and starting your car to drive to work.  All these things can be operated by computer software and you haven’t even had your morning coffee yet; which by the way, can also be done by utilizing computer software.  Most of us don’t even realize that software is behind so many of our daily functions until, that is, when something goes wrong and we are impacted somehow.  This brings us back to the monitoring software that is used to notify someone when there is a problem.