Thanks for using Apple Support Communities.
For more information on this, take a look at:
be sure to authorize the computer before connecting the device.
iTunes Store: Transferring purchases from your iOS device or iPod to a computer
Please note that this feature works only for items that were purchased on the iTunes Store. Any items imported from audio CDs or acquired from other sources will not copy from your device to the iTunes library.
Best of luck,
Thank you for using the Apple Support Community. Due to the nature of your issue or question you may find more information by using another one of Apple's support resources - https://expresslane.apple.com/GetproductgroupList.action.