Follow the below steps to Sync iPhone, iPad, or iPod to iTunes.

How to Transfer Music from iTunes to iPhone, iPad, or iPod

Step 1. Download the iTunes from here and install in your PC

Step 2. Once the iTunes get install in your PC open the iTunes app and click on sign in to the iTunes store

Step 3. Login with your register apple id

Step 4. After successfully login click on the Store button

Step 5. Click on Purchase to get music from iTunes to iPhone

Step 6. Click on the button marked in the image and your song will get download

Step 7. Your downloaded song will be available in your pc at the place Music\iTunes\iTunes Media\Download

Step 8. To transfer this in your iPhone connect your iPhone with your computer via USB

Step 9. Now click on Music where you can check available song in your iPhone

Step 10. Go the download folder and copy the song

Step 11. Paste the song in iTunes Music

Step 12. That’s how you can transfer iTunes to iPhone music.