If for some reason you are unable to use either type of voicemail and can’t seem to get it figured out for the life of you, it could be a good idea to contact your cell provider to see what your options are and why your voicemail might not be working.
1. Launch the Phone application. The numeric keypad can be found near the bottom of the screen if you don’t notice it immediately.

Navigate to your Phone app located at the bottom of your iPhone home screen. Tap-open the Phone app. Once you have done that, you will see a voicemail logo the bottom right corner of the window that has opened, select that voicemail icon. That action will open the visual voicemail interface. At first, all you will see is a blank screen with a
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.