In Appium, you don't need to worry about the operating system of your mobile device because the Selenium Webdriver commands are converted to Android and iOS ____ commands according to the device type rather than the OS type of your mobile device.

Appium is an open-source, cross-platform test automation tool for native, hybrid, mobile web and desktop apps. Appium is used for automated testing of native, hybrid, and web applications. It supports automation test on the simulators (iOS) and emulators (Android) as well as physical devices (Android and iOS both).