How to Answer Voicemail on an iPhone
If you miss a call on your iPhone, or just don't feel like answering, that call goes to voicemail. If your caller leaves you a message, you will be able to find that message in the Voicemail center on your iPhone. Messages stored there can be deleted immediately or listened to again and again. The call can even be returned from that same screen, eliminating the need to navigate through the Phone application.
Tap the "Phone" icon on the bottom dock of your iPhone's Home screen.
Tap "Voicemail" on the bottom right corner of your screen. A red alert badge will notify you if you have a voicemail.
Tap an unheard message once to listen to it. All unheard voicemail messages will display a blue circle to the left of the screen.
Tap an old voicemail message once for the "Play" button to display, then tap the "Play" button to listen.
Tap the green "Call Back" button at the bottom of the screen to return a call.
Tap the red "Delete" button at the bottom of the screen to delete a message.