There are two main types of software: systems software and application software. Systems software includes programs that manage the computer itself like the operating system, file management utilities, and disk operating system. Without systems software installed, users would have to type all instructions. Application software, also called productivity programs, enable users to complete tasks like creating documents, spreadsheets, and playing games. Application software is specific to the task it is designed for, from simple calculator apps to complex word processors, which already set document formatting defaults that users can customize.