The telephone systems have the feature named as Voicemail. VoIP is the best example of it. When a receiver is unable to pick up the phone, then the caller can leave the voice message on the receiver’s phone. In older telephonic machines, such messages were stored as a voice message directly, and the receiver can hear them later. In modern telephone systems, such info is being stored on the server of the service provider in the user’s mailbox. It is similar to email in which the messages are saved in the form of audio instead of text.
1.) Você está conectado à caixa de correio de John Doe. Atualmente, o Sr. Doe não pode atender. Você pode ligar novamente mais tarde ou deixar uma mensagem com seu nome e número de telefone que o Sr. Doe irá lhe retornar o mais rápido possível.

To enable Visual Voicemail, you must create a password by accessing your voicemail and then record a greeting as follows: Access the Telephone app, select the Voicemail tab and tap Configure now. Select a password for your voicemail and tap Done. Confirm your password by re-entering it and tap Done. Select Custom if you wish to save a new greeting or Default if you don’t wish to edit your message. Tap Save.
If a phone rings once and then goes to voicemail or rings only briefly, it You can't definitively know the cause of a phone barely ringing and going to voicemail because neither a phone company nor the phone's operating system provider will tell you if your phone number is blocked.