I need to send push notifications to iOS and Android on a new mail in cpanel

I have developed applications to fetch data from IMAP with PHP as backend and my applications are in swift and kotlin for ios and android respectively I'm not able to send notifications cause I don't know on what event it should push notification Details: Right now there are 2 applications android and iOS which fetch the mail information from a PHP Application with Rest API calls I need a developer who can write a code/script to send a notification with either FCM or Onesignal orAWS SNS or something making sure both iOS and Android can fetch those notifications The main problem I have is identifying the even on which to send the notification i.e as the mail arrives at the respective inbox just like Gmail does Since there is confusion in understanding the requirement updating it again: The event goes like this I would create a cpanel account in my WHM->goto cpanel and create a new mail-> so as soon as I send a mail from gmail or any other mail to the newly created email or even a mail to self from the newly created email there should be a notification sent to Android and iOS