Apple Developer Portal Configuration

Enable push notification for an app

Apple Developer Portal -> Certificates, Identifiers & Profiles -> Identifiers -> Select App IDs

Select Your App Bundle Identifier -> Checkmark Push Notifications

Apple Developer Portal -> Certificates, Identifiers & Profiles -> Keys -> Register a New Key (Press blue plus)

Give Key a Name -> Checkmark Apple Push Notifications service -> Continue

Keep the APNS key file safe as it is required during stage two.

Apple Developer Portal -> Certificates, Identifiers & Profiles -> Identifiers -> App Groups

Add a new App Group -> The identifier must be of the form group.com.MyApp

Make a note of the identifier for this app group.