what is iTunes match?

A service which matches tracks you've gotten elsewhere to ones available in the iTunes Store and makes them downloadable from Apple's servers. Its benefits are bundled with Apple Music and Apple One; you don't need it if you're subscribed to either of those.

(234892)

To learn more about Match, read this article --> Subscribe to iTunes Match - Apple Support

You don't need it if you have Apple One or Apple Music subscriptions. It's a cheaper alternative to Apple Music that does not offer downloading of non-purchased music from Apple. It's good if you have a large CD collection and no real interest in Apple's music collection.