The prompt will stop appearing. If the 611 Automatic System does not work for your carrier, you can head to your carrier‚Äôs official website if youriPhone 6s keeps asking for voicemail password. From the myWireless Account home page, select Phone/Device then choose the Reset Voice Mail PIN link from the left column. Note: If there is more than one line on the account, make sure the correct wireless number is displayed in the Wireless Number list before selecting Reset Voice Mail PIN. To reset the password for any of the lines on the account, choose a wireless number from the dropdown menu and click Submit. In a while, iPhone will display "Password Incorrect - Enter Voicemail Password." Enter the last seven digits of the wireless phone number and tap OK. Log into My Verizon with your cell phone number and password. If you've set up a username, use the username instead of your phone number. Select My Verizon> Reset Voice Mail Password. Choose your cell phone number from the drop-down menu, and thenclick on "I Will Create My Own Password." Enter and confirm your new password. Click on "Submit" to save the change. Sign in to My Sprint with your username and password. Click“My preferences” tab. Under Things I can manage online, click on Change voicemail passcode. Enter your new passcode and confirm. Tap Save and you will get a message informing you the new password has been saved.
With this method, you don’t need a third-party app. Call the person you want to chat with, then tap the “Add Call” button on your phone’s screen. Dial your own phone number—the one you’re calling from. This will take you to your voicemail. Once your voicemail has started recording, tap the “Merge Calls” button on your screen. Now, you’ll record your phone conversation onto a voicemail message. When you’re done with the call, you can tap the share button to export it to your Mac via Airdrop, to the Voice Memos app, or transfer it via email or text message. The file is recorded as an M4A, so depending on what you want to do with it, you may need to convert it to MP3 before uploading it to other apps.

While this app has the exact same name as the iOS app we listed above, it’s made by a completely different developer. This version includes customizable skins and the ability to record calls or notes as MP3s. Instead of having to tap a button, you can also simply shake your phone to instantly start recording a call. You can also choose to sync your stored calls with Dropbox and select particular contacts whose calls you always want to record (and store).
Website: https://www.digitaltrends.com/mobile/how-to-set-up-voicemail-on-an-iphone/