The very first thing to be checked is, have you set up the voicemail earlier or directly recording the voicemail greeting? If you haven’t already set up the voicemail and unable to record voicemail greeting, then go to the top of the page and learn how to set up voicemail on the iPhone.
To change the voicemail password of your iPhone, follow the following easy steps. Step 1. On your iPhone, go to settings and click "Phone". Step 2. On the Dropbox that will appear, click "Change Voicemail Password". Step 3. When prompted, enter your current password and click "Done". Step 4.

To call your voicemail on an Android phone, simply open your phone’s dial pad and hold your finger down on the “1” key. You can also call your voicemail from a different phone by calling your own number and tapping the pound key. Navigate to your voicemail option if using a cell phone. … Listen to the recorded voicemail instructions. … Press the number on your keypad symbolizing “Yes” when asked if you want to delete your current message. … Select to record your own message if you want, or leave it as the mechanic default message. Step 1: Press # Right after you realize you want to delete your voicemail press the # symbol. It is VERY important that you do not hang up the phone. … Step 2: Listen to Menu. Once you press # on your phone, you will automatically be given access to a menu.
You can disable voicemail by dialing ##002# on your phone. That disables all call forwarding so no calls will go to voicemail. I use Google Voice for voicemail so I disabled it on the cellphone side.