Can’t thank you enough!!!! I’ve been living without my voicemail for about a month, putting off fixing it or finding someone who can. Decided to Google it, found your fix it page and in under 5 minutes it’s fixed!!!
Website: https://www.mvorganizing.org/how-do-i-find-out-what-my-voicemail-password-is/

On the Greeting page there are two options. The standard option is to use the default iPhone voicemail message, but you can also record a custom message. If you already have a custom iPhone voicemail message recorded, tap Play to listen to it now. Otherwise tap Custom.
Open the Phone app . Press and hold “1” to call your voicemail. Enter your PIN and press “#”. Press “*” for the menu. Press “4” to change settings. Press “1” to change your greeting. Follow the recorded instructions. How do I change my voicemail message? From the Home screen, tap the Phone icon . Tap Voicemail then tap Greeting (upper-left). Greeting is located in the top-left corner of screen. Tap Custom to record a greeting. Enabled when a checkmark is present. Tap Record to begin recording the custom greeting message. Tap Stop to end recording then tap Save. Call *86 (*VM) from the handset or the 10-digit mobile number from another phone. Follow the instructions for choosing the language options then press the # key to confirm the choice. When prompted, enter the 4-7digit password then press the # key. When prompted, say the signature (or name) then press the # key. Open your Android’s Phone app. It usually looks like a phone receiver at the bottom of the home screen. Press and hold the 1 key on the keypad. Tap Add number. Tap Service. Tap My carrier. Tap Setup. Tap Voicemail number. Type your mobile phone number and tap OK.