On your device, go to the Home screen (the one with all the icons), and tap on the Settings icon.

Scroll down and tap on About phone or About tablet. Some information will appear. If one of the lines of information says Android with a version number, you have an Android device.

If you do not see About phone or About tablet, look for an iCloud option. If you see this option (you don't have to select it), that means you have an iOS device.