Open the Music app on your iPhone
Search for the song, album, or playlist you want
Tap the Download button next to the item
If you do not see a Download button, tap the More button and look for Download
Make sure you are signed in with your Apple ID
Turn on Sync Library in Settings if you use Apple Music
Connect your iPhone to Wi-Fi for faster downloads
Check your storage space if downloads do not complete
Open Settings
Tap Music
Turn on Automatic Downloads if you want music to download automatically
Use the iTunes Store app to buy music if needed
After purchase, tap Downloads in the iTunes Store or Music app
Use a computer and the Finder or iTunes to sync music to your iPhone
Connect your iPhone to the computer with a cable
Select your iPhone in Finder or iTunes
Choose Music and sync the songs or playlists you want
Tap Downloaded Music in the Music app to find saved songs
Remove and re-download music if a download gets stuck