Audio-in Port?

Hi Forum Folks,

Running an Inspiron 5755 (2017 vintage).

I'm setting up to switch to a new Tracfone, and there are voicemails in my old one I want to save to *guarantee* that they won't disappear in the process.  They're from my recently deceased mother, and I *don't* want them to disappear somehow.  I'd feel a whole lot more secure if I could back them up to my hard drive or a DVD or flash-drive before I even start the transfer process.  

I've found several methods using various software combinations that will work, but they all involve an "audio-in" port on the computer.  The only audio port of any kind I can find in this machine is a headphone jack, which would seem to be an outbound port only... but I've read that in some machines, it's a combination out and IN port as well.  Is this the case for this machine?

Thanks for any input!