Make sure that the specific notifications you want are active in your smartphone or tablet’s notification center.
For iOs, go to Settings, then Notification Center. Make sure the apps you want are in the “include” list. To set the details for a particular app, click on the app in the include list and customize to your preferences. Keep in mind the notification must be ‘unread’ to be posted to the notification center.
For Android, go into the application of interest and activate notifications within that app to ensure it will post alerts to your phone’s notification drawer. Keep in mind the notification must be ‘unread’ to be posted to the notification drawer.