General

I haven't done any recording of voicemails, but I have done a lot of media recording (vinyl, cassette tape, etc.) into my computer.

Use a patch cord to take the output from headphone jack (not speaker output) and connect to the "line in" input jack of your computer's sound card. I use RIPVinyl or Roxio Media Creator to record. I haven't tried it, but you might be able to connect into the Microphone jack of the computer and use Windows Voice Recorder.

It should be possible to do this from a phone output jack.

If you are talking about a voicemail on an answering machine, you may just have to record speaker to microphone using your cell phone recording app.

You can't capture the original source audio perfectly unless you involve some hardware like mentioned above. The simplest way is to record while the vmail plays on speaker.

I did this once by just calling the number that replies with the message, having my phone on speaker, and recording that output via a device that handled noice cancelling and clarity well while recording. It was some vidcam or an older phone that I then just copied the file to a mem card or emailed myself via wifi. It wasn't amazing but the vmail I wanted was recorded via cell phone so it was already a bit garbage.

You can practice by recording a youtube video playing on your phone or some other device with audio on speaker.

I haven't used it in a while, but Audacity is free sound recording software that has tools for cleaning up sound files. You can amplify the volume, remove dead spaces, etc. There is also a noise reduction feature where you scan a section of just noise and it uses that sample to remove noise from the entire recording or any section you highlight.

If they have an iPhone it's super easy.

I'm talking downloading a voice mail someone left you though.

Android or Iphone?

It's an iPhone. I want to save their voicemail

Where you listen to the voice mail, there's a share button you tap (it's to the left of the letter "i" info button and above the play, speakerphone, call back, trash controls).

Your options are sending to a contact, saving to files (icloud or locally), opening in an app. I usually open it in Gmail and send or save to icloud. Then I can open it on a computer.

It's their voice mail message not one left for me.

I seen a really cool gadget at CES this year that would be PERFECT for this:

https://www.magmoglobal.com/magmo-pro


a cheaper way would be to setup virtual voice mail. It has to be supported by the carrier and you can always just spend the few bucks for the month, but it does allow you to at least download the voice mail so you have it in a file.