Software is the programs and instructions which are run by a computer system. Some software, for example, operating systems, tell a computer what to do, how to interact with the user, and how to control its hardware. This type of software is known as systems software.
Other software, such as games, word processors, spreadsheets and instant messaging, allow the user to perform a specific task. This type of software is known as applications software, often abbreviated today as apps.
All computers require software to run. A smartphone is made up of hardware. These are the parts you can see and touch, including the screen, processor, memory and many other elements hidden inside the phone.
However, mobile phones also use software. They run on an operating system such as iOS or Android, and have apps which allow the user to do things like take photographs and send tweets. Modern smartphones allow users to browse the internet, edit videos, access their bank accounts, video conference, play games, navigate their cars and much more.
Without software most hardware is useless. Even everyday items such as printers, central heating boilers and washing machines are equipped with software which tells them how to work. If your washing machine broke down an engineer might just update the software (called firmware when it’s embedded on a device) to get it working again, without having to replace any physical parts.