Voice mail is a network feature offered by most networks. It is similar to an answering machine and allows the caller to leave a voice message if the person called is unavailable.
This feature means that the person who received the message can listen to it whenever necessary.
Most cell phone services offer voicemail as a basic feature; many corporate private branch exchanges include versatile internal voice-messaging services, and *98 vertical service code subscription is available to most individual and small business landline subscribers (in the US).