How do I copy a playlist to a thumb drive
I want to copy a playlist from Itunes to a thumb drive so it can be played in my car
iMac 21.5″, macOS 10.13
I'm not sure about exporting an actual playlist – but you should be able to drag-and-drop songs out of the iTunes (or Music) window onto the thumb drive. This will work with songs you have purchased on CD or from the iTunes Store. There's no point in doing it with offline listening copies of Apple Music subscription songs - as those have DRM that would prevent them from being readable by a car stereo.
Note that the Finder likes to put hidden metadata files onto non-Mac filesystems. Ones called .DS_STORE and the like probably won't confuse your car stereo. However, ones with names like
._SONG1.MP3
._SONG2.MP3
._SONG3.M4A
may cause trouble.