Saving and sharing voicemails on iPhone is remarkably simple, but since it’s a fairly new feature many users are not aware it exists. You’ll need iOS 9 or newer to have this feature available in the Voicemail section of your iPhone Phone app.
Open the Phone app on the iPhone and tap on the “Voicemail” button
Tap on the voicemail message you wish to share or forward to, then tap on the share button, which looks like a little square icon with an arrow pointing out of it
•Choose “Message” to send the voicemail as text message or iMessage to a recipient
•Choose “Mail” to email the voicemail to a recipient (or yourself)
Fill in the recipients contact name, phone number, or email address and send the message or email as usual
A shared voicemail delivered through messages or email will arrive as a .m4a file labeled as “voicemail-#.m4a”, this is the same type of m4a audio file that many audio players can recognize, including iTunes, which makes the shared voicemails universally available to just about any recipient, whether they’re on iPhone, iPad, Android, Mac OS X, Windows, or Blackberry.