Authorize New Computer

• 1). Download iTunes to your new computer. Open the iTunes software.
  
  
• 2). Click the "Store" menu on the top bar. Select "Authorize This Computer" from the list of options.
  
  
• 3). Sign in to your Apple account using your AppleID and password. Click the "Authorize" button.
  
  

Transfer Additional iPhone Files

• 1). Plug a flash drive into your old computer.
  
  
• 2). Copy any files that you did not purchase using iTunes to the flash drive. This includes photos and MP3 files you converted from CDs.
  
  
• 3). Plug the flash drive into your new computer.
  
  
• 4). Paste the files on the flash drive onto your new computer.
  
  

Transfer Purchases

• 1). Plug your iPhone into your new computer using your iPhone USB cord.
  
  
• 2). Choose the option to "Transfer purchases."
  
  
• 3). Edit the settings on the iTunes screen to upload the files you pasted from your old computer. Designate a folder from which to upload photos. Sync your iPhone to the new computer.
  
  
• 4). Click the "File" menu. Choose the "Add file to library" option. Designate the folder where you saved your MP3 files. Sync your iPhone.