Mobile devices are the primary target for Android applications, but Android applications can also run on ChromeOS devices. This is important because ChromeOS devices are laptops, or at least support a laptop mode, and mobile and laptop devices have different input capabilities. Applications can target both types of devices at the same time. For more information:
Android devices include a touchscreen keyboard. When you select editable UI elements such as Input Fields Unity automatically activates the Android touchscreen keyboard and handles input from it. For information on how to manually activate and configure the Android touchscreen keyboard, refer to Mobile Keyboard.