To activate Visual Voicemail, dial 1217 from your iPhone and a recorded message will confirm it has been switched on. When a message is left in your voicemail mailbox, you'll see a notification against the ‘Phone’ widget on your iPhone. When you activate Visual Voicemail, your current personal greeting will carry over.
Because you never know the quality of someone’s phone audio or your cell phone service, it's not a bad idea to give your name and phone number twice within your message. The thought being, if the person you called can’t understand who you are or how to call you back, how can they be expected to return your call?

When we call our friends and family, we often call and hang up without leaving a voicemail -assuming the missed call will be notification enough that we want this person to call us back. Even though this is acceptable to do in our personal lives, phone call etiquette in the corporate world plays by different rules.
Follow the instructions and press that number. You will be asked to delete your current Voicemail greeting. Click on the ‘Yes’ button that appears on the screen if you want to remove that. You can save your new recorded Voicemail greeting or can use the default recorded option. From the home screen, select the Phone app. Note: Alternately, you can set up voicemail by selecting the Phone app then selecting and holding the 1 key. Select Keypad, then select the Visual Voicemail icon. Select Start. Select Ok. From any Home screen, tap the Menu key. Tap Settings. Tap Call settings. Tap Voicemail. Tap Voicemail again. View the voicemail number. Press and hold the 1 on your device’s dial pad to call and connect to your voicemail. Press the star * key to access the main menu. Press 4 to access the mailbox options. Press 7 to change the language of the voicemail prompts to either Spanish or English.