Update ios.md for Events (#9)

* Update ios.md

* Update ios.md

Author: Mohtasim

articles/communication-services/how-tos/ui-library-sdk/includes/events/ios.md

@@ -10,20 +10,28 @@ ms.service: azure-communication-services
 
 ## Participant joins the call
 
-We expose `addOnRemoteParticipantJoinedEventHandler` to listen if the participant joins the call.
+We expose `onRemoteParticipantJoined` to listen if the participant joins the call.
 
 ```swift
-
-
-
+let onRemoteParticipantJoinedHandler: ([CommunicationIdentifier]) -> Void = { [weak callComposite] ids in
+            guard let composite = callComposite else {
+                return
+            }
+            /// ids are the communication identifiers that has joined and are present in the meeting
+        }
+callComposite.events.onRemoteParticipantJoined = onRemoteParticipantJoinedHandler
 ```
 
 ## Participant left the call
 
-We expose `addOnRemoteParticipantLeftEventHandler` to listen if the participant leaves the call.
+We expose `onRemoteParticipantLeft` to listen if the participant leaves the call.
 
 ```swift
-
-
-
+let onRemoteParticipantLeftHandler: ([CommunicationIdentifier]) -> Void = { [weak callComposite] ids in
+            guard let composite = callComposite else {
+                return
+            }
+            /// ids are the communication identifiers which have left the meeting just now.
+        }
+callComposite.events.onRemoteParticipantLeft = onRemoteParticipantLeftHandler
 ```