Computer cannot be used without a software in it. It is the software which gives instructions to the hardware of the computer so as to work all devices in tandem.
A software is nothing but a set of programs. The machinery of computer requires at least an operating system software to make it work. These programs can be of different types. They may help you to write letters, draw pictures, prepare tabular data, or manage your accounts. A program is set of instructions. These instructions are usually of one line each. To use a software one has to have the knowledge about the use of that software.
There are basically two types of software: