iPhone: How to reset or change voicemail password
Summary
Information on how to reset or change your voicemail password on iPhone is available from your wireless carrier.
Products Affected
iPhone
If you don't remember your voicemail password or need to change it, contact your wireless carrier for assistance.
If your wireless carrier offers Visual Voicemail, you can change your voicemail password directly from the iPhone. Tap Settings > Phone > Change Voicemail Password.
Additional Information
Resetting your AT&T voicemail password
If you are prompted for your voicemail password on iPhone and you do not remember what it is, you can press the ? button in the password field to display an option to call AT&T for assistance. Listen to and follow the menu prompts to reset your voicemail password:

If you need additional assistance, contact AT&T.
Important: Mention of third-party websites and products is for informational purposes only and constitutes neither an endorsement nor a recommendation. Apple assumes no responsibility with regard to the selection, performance or use of information or products found at third-party websites. Apple provides this only as a convenience to our users. Apple has not tested the information found on these sites and makes no representations regarding its accuracy or reliability. There are risks inherent in the use of any information or products found on the Internet, and Apple assumes no responsibility in this regard. Please understand that a third-party site is independent from Apple and that Apple has no control over the content on that website. Please contact the vendor for additional information.
Twitter
Facebook