There are several ways that the system can alert you when you have a new message.

Message Waiting Lamp
Most Avaya telephones include a message waiting lamp, typically at the top right of the phone. This lamp lights when your mailbox contains any new messages that you have not heard. In addition, many Avaya phones have a MESSAGE button which also lights when your mailbox contains new messages.

Outcalling allows you to specify a number that the system calls when your mailbox contains any new messages. If you answer the call, the system prompts you to login to hear your messages.

Voicemail Email
The voicemail system can send an email whenever your mailbox receives a new message. The email can be just a simple alert that you have a new message or it can also include an attached copy of the message.