music library on icloud

Hi b Adrian,

Thanks for coming to Apple Support Communities for help today.

What you are describing sounds like iTunes Match. Here are the steps: Subscribe to iTunes Match.

"Subscribe to iTunes Match

1. On your Mac, open the Apple Music app. On your PC, open iTunes for Windows.
2. On your Mac, go to the sidebar and click iTunes Store. Don't see the iTunes Store on your Mac? On your PC, click Store at the top of the iTunes window.
3. Scroll to the bottom of the Store window. Under Features, click iTunes Match.
4. Click the Subscribe button.
5. Sign in with the Apple ID and password.
6. Confirm your billing information. You might need to add a valid payment method. Then click Subscribe.

After you subscribe, iTunes Match automatically scans your music library for matches. A status indicator lets you track the scan's progress. You can manually pause and resume the scan at any time by clicking the Stop or Start button.

It might take some time for iTunes Match to upload your music from your Mac or PC. If your Mac or PC disconnects from the Internet during the upload process, iTunes Match will automatically resume where it left off the next time you open the Apple Music app or iTunes for Windows.

Once your music library is uploaded, you'll see the Download button next to songs that are available in iCloud. If you don't see the Download button, then the song is already in your local music library."

Once complete, you could (and should) store your Music library on an external drive.

Have a fantastic day!