Hi,
To send push notification to Android and iOS, you need to configure your Android and iOS App by integrating our SDKs in your app. You need to follow our Android and iOS tutorials to prepare your app for sending or receiving Push Notificaion. Once you complete the device side setiings then you can use our PHP SDK to send push notification to both the devices.
Let me know if you have any other queries, I will be happy to help you.
Regards,
Rajeev