The default method of getting music from your Mac/Windows to your iPhone/iPod Touch is to add the music to your iTunes library and then sync the library with the mobile device. What if you want the music on your mobile device, but don’t want to add it to your iTunes library? Here’s the solution to transfer music to iPhone (or iPod Touch/iPad) without adding it to the iTunes library.
1. Open iTunes and connect your mobile device to your Mac/Windows.
2. Click on the device on the left pane and select “Summary”. Under the “Options” section, check the box “Manually manage music and video”. Click “Apply”.
3. Now you can drag your music from the desktop (or any other folder) to the “Devices” section in the left pane.
That’s it. The song/video will only be added to your mobile device, and not iTunes library.