How do I upload music from a harddisk to iCloud

To upload music from an external hard drive to iCloud and stream it across your devices, you need an active subscription to Apple Music ($11.99 per month) or iTunes Match ($24.99 per year). iTunes Match only stores and matches your library; it does not give you access to the Apple Music streaming catalog).

1. Connect your hard drive to your computer.
2. Open the Music app (or iTunes), go to Preferences/Settings, find the file settings, and deselect the option to copy files to the media folder when adding them to the library (so they stay safely on your external drive).
3. Ensure Sync Library is enabled on both your computer and your iPhone/iPad (under Music settings).
4. Import tracks: In the computer's Music app, select File > Add to Library and choose the music directly from your hard drive.
5. The app will match or upload your tracks to iCloud. Once finished, you can stream them on any device linked to your Apple ID, even without the hard drive connected.

You may be able to copy your music data to iCloud, but your devices can not stream your music from the folder you did create in iCloud for this purpose.

According to Apple, the location of the Music folder should not be changed.

Change where your music files are stored on Mac - Apple Support

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Connect your device to your Mac to sync Music content - Apple Support

Sync content between your Mac and iPhone, iPad, or iPod touch - Apple Support

Do you have an Apple Music subscription?