Sync music from iPad to iPhoneX
How do I sync music from my iPad to my iPhoneX both use the same Apple ID
iPhone X, 13
You don’t.
Purchased music from the iTunes store can de re-downloaded by following the steps here: Redownload apps, music, movies, TV shows, and books - Apple Support
For anything else, you need to sync it from the computer you synced it to the iPad from: Use iTunes to sync your iPhone, iPad, or iPod with your computer - Apple Support