Ipod

If you purchased the music from the iTunes Store, directly on your iPod, simply sign into your iTunes account in iTunes on your computer and download your purchases.

Apple Music is a monthly subscription service. When Apple Music is used, you do not buy the music, you simply have access to it while you pay the monthly fee. This means that when you end that subscription you will no longer have access to that music.

You do not need to use Apple Music just to get the music you've purchased.

Hello,

You would need to subscribe to either iTunes Match or Apple Music on your computer. This will store your entire Music library in iCloud. This cannot be done directly on iPod.