Apple: Any iOS device that supports iOS 15 or above
Android: Any Android device that supports Android 9 or above
a) How do I see my iPhone/iPad iOS version and Model?
Select General --> Settings --> About. Software version is the iOS and the Model Name is the device.
b) How do I see what build my Android device is using?
Scroll to the bottom of your settings app and locate About phone. Enter the About phone section. Look for an additional submenu for software information, or you may see a section labeled Android version. Enter this section of your menu.