Here’s how to change your voicemail on an iPhone:
Open thePhoneapp.
If you haven’t changed your voicemail greeting before,Defaultwill be checked.
If you already have a custom message that you’re changing,Customwill be checked.

you’re free to skip this step
TapRecordand speak the voicemail greeting you want.
When you’re done with the message, tapStop.
To listen to the message, tapPlay.

If you like the greeting and want to use it, tapSave.
If you want to change the greeting, tapRecordagain, speak a new greeting and tapStopwhen you’re done.
Review it by tappingPlay, and save it by tappingSave.

If you still can’t change your greeting, tryresetting your data pipe tweaks.
To delete your custom voicemail greeting, kick off the Phone app and tapVoicemail>Greeting>Default.
To record a new greeting, tapCustom>Record.
Todelete voicemail on an iPhone, initiate the Phone app and go toVoicemail.
Tap the message, then tapDelete.
To delete multiple messages, tapEdit, choose your messages, and then tapDelete.