Restore Apple Music library tied to Apple ID

You will need to provide more details:

• Is this from playlists/downloads lost that were done from a previous Apple Music subscription that has lapsed or cancelled?
• Were these purchased songs from iTunes that you want to download again?
• Did you manually sync the music to your iPhone from a Mac or PC?
• Do you have an Apple Music subscription for automatically syncing Music across devices?
• Did you wipe your device and need to turn on Sync Library again in Settings for the Music app.