A Smartphone is a mobile computer (Mobile referring to being portable). Smartphones are all cellular devices that have an Operating System (OS). Most people associate Smartphones with touch screens. While this may be the case, some Feature Phones (phones with buttons) have Operating Systems which basically makes them Smartphones.
They are two major Operating Sytems in the Smartphone industry. iOS Operating System and Android Operating System. iOS Operating System was created by Apple and only used in Apple product such as iPhones and iPads. Android was created by Google and operates about 99% of Smartphones that are not made by Apple.