In simple words, computer software is nothing but a single or a set of computer programs that tell the computer what to do, and how it should be done. That means, whatever you instruct the computer to do, using input devises like the keyboard and the mouse, is translated by the software into a language that the computer understands.
Software can be broadly divided into - programming software, application software and system software. While programming software acts as a tool to design new software programs, the systems software helps in the basic functioning of the computer hardware and the system. The systems software plays an important role in ensuring that all the hardware components of your computer, including the I/O devices, the printers, cameras etc work in a synchronized fashion.
Application software is any software that is designed for helping the users to perform specific tasks on the computer. For example, Internet Explorer is an application software that helps you access the webpages on the internet. Also, the video games or music players that you install on your computer or laptop are examples of application software.
Software can be OEM software, which developers like Microsoft usually provide it to end-users through the hardware providers like Dell or HP. Shareware is a type of software that can be downloaded from the internet for a fee. Shareware can also be tested for free, during the trial period as defined by the developer.
Freeware is a type of software that can be entirely downloaded from the internet for free. Demo software is used to demonstrate the functions of the software and let the user get a feel of the product before purchase. Software packages, including OEM software, which can be purchased directly from a retail store, are categorized under retail software. | 
