This question already has an answer here:
My 2013 MacBook Pro allowed me to convert audio from old cassette tapes and vinyl to digital by using a 3.5mm Male To Male Stereo Audio Cable from the player's headphone jack into the headphone jack of the MacBook Pro 2013. In the System Preferences, you could change the headphone jack to function as input rather than output. Easy. You could use Quicktime to record and other apps.
I found some old vinyl albums that I want to convert to digital but my 2015 MacBook Pro does not seem to be able to do what I mentioned above. Playing the music over the air and recording using the internal microphone would not be acceptable.
Suggestions to accomplish this?