If your iTunes library is getting a bit out of control, you can clean things up by deleting music you no longer listen to. When you remove songs from your iTunes library, they'll be removed from any devices they're synced to next time you...
Method 1 of 3:
Mac and PC

Launch iTunes on your computer. You can delete any of the songs in your iTunes library directly in iTunes.

Open your music library. Click the Music button in the upper-left corner and then click the "My Music" tab.
Find the song that you want to delete. Depending on your settings, you may see a list of all of your songs, your albums, or the artists in your library. You can click the menu in the upper-right corner to switch views.
Right-click the selected music. If you're using a Mac with a one-button mouse, hold ⌘ Command and click your selection.
Select "Remove Download" to delete the local copy (purchased music only). This will remove the downloaded file, and you'll see the iCloud Download button appear next to it.
Select "Delete" to delete the selected items. What actually happens will vary depending on the item you are deleting:Method 2 of 3:
iPhone, iPad, iPod touch

Open the Music app on your iOS device. You can delete any of the songs on your iOS device from with the Music app.

Find the song, artist, or album you want to delete. You can switch between views by tapping the menu at the top of the list of music.

Tap the "..." button next to the song, artist, or album. This will open a new menu.
Tap "Delete." You may have to scroll to see this option.
Tap "Remove Downloads" or "Delete from My Music." These two options do different things, depending on if you are using the iCloud Music Library or not:
Delete all of your local music files at once. If you're trying to clear out a lot of space on your iOS device, you can delete all of your stored music at once. This will not affect your iTunes library or iCloud Music Library:[2]Method 3 of 3:
Unhiding Your Purchases

Open iTunes on your computer. The only way to restore your hidden purchases is to use iTunes on a computer.

Sign in with your Apple ID if you aren't already. You'll need to be signed in with the account that you purchased the music with in order to find your hidden purchases.
Click the "Account" (Mac) or "Store" (Windows) menu and select "View Account." You'll be prompted for your Apple ID password again.
Find the "iTunes in the Cloud" section. You may have to scroll to find it.

Click "Manage" next to "Hidden Purchases." This will display all of the purchases you have hidden from your library.

Click the "Unhide" button to restore songs. You'll see this button underneath each album that you've hidden. You can click the "Unhide All" button in the lower-right corner to unhide all hidden songs at once.

Find your unhidden songs. The songs you've unhidden will appear back in your iTunes music library.[3]
Update 05 March 2020
ncG1vNJzZmismaXArq3KnmWcp51ktbDDjK2mZpyVobK1sYyspqefo2Kzs7vMZqCtrZ6awA%3D%3D