You can add AirPods charge widgets on your iPhone, iPad and Apple Watch. On Mac, there is no built-in option to add a charge widget. However, you can check the charge of AirPods and case through Menu Bar or System Preferences.
To find out if you need a firmware update, first check what firmware version is installed on your AirPods. On your iPhone, you need to open Settings and go to Bluetooth. On a Mac, the steps will be different depending on the macOS installed.