i cant sync music to my phone whats the reason if it keep telling me waiting for changes to be applied? how can i make changes?

Check to see if there's an iTunes update available for your computer.

Mac

1. Open iTunes.
2. From the menu bar at the top of your computer screen, choose iTunes > Check for Updates.
3. Follow the prompts to install the latest version.

Windows

1. Open iTunes.
2. From the menu bar at the top of the iTunes window, choose Help > Check for Updates. Learn what to do if you can’t see the menu bar.
3. Follow the prompts to install the latest version.