5. Hit “Record” on Audacity. Then, on your phone, play the voicemail you’d like to record. When your message is done, stop recording. If you want to get really fancy, you can use Audacity to chop off any dead air at the start or end of your recording.
Not all carriers support Visual Voicemail, but most major ones do. Visual Voicemail will work automatically as long as you’ve set up regular voicemail on your iPhone. Tap the Phone app icon to open it.In the bottom toolbar of the Phone app, tap the Voicemail icon.On the voicemail screen, you’ll see a list of all the voicemails people have left you. Tap any voicemail on the list.When you tap a voicemail on the list, it will expand to show a set of controls as well as the iOS transcription of the voicemail. If you want to read the transcription without hearing the voicemail, you can do that right here. Alternately, you can tap the play button to hear the voicemail. Save And Share Voicemails

4. Provide your voicemail system's password. You will be prompted to enter the passcode to your voicemail account, if you have set one (which, hopefully, you have).
This tutorial is going to show you how to record a voicemail greeting that you choose. It is a good idea to either write out or think about exactly what you are going to say before you record the message. You will then have the opportunity to play the greeting back before you set it for any incoming calls that go to voicemail.