What is the difference between information technology and software industry?

Information technology is the use of computer to store, retrieve, transmit and manipulate data or information, often in the context of business or other enterprise. Whereas the software industry includes businesses for development, maintenance and publication of software that are using different business models.

Every software company is an IT company but every IT company may not be a software company. For example, a hardware company is an IT company but not a software company. IT company is the general term. It may be an IT service company or software product company.