To convert a song’s file format:

  1. Open iTunes Preferences.
    Windows: Choose Edit > Preferences.
    Mac: Choose iTunes > Preferences.
  2. Click the General button, then click the Importing Settings button in the second section of the window.
  3. From the Import Using pop-up menu, choose the encoding format that you want to convert the song to, then click OK to save the settings.
  4. Select one or more songs in your library, then from the Advanced menu, choose one of the following (The menu item changes to show what’s selected in your Importing preferences):
    • Create MP3 version
    • Create AAC version
    • Create AIFF version
    • Create WAV version
    • Create Apple Lossless version

If you haven’t imported some songs into iTunes yet, you can import and convert them at the same time. This will create a converted copy of the file in your iTunes Library based on your iTunes preferences. To convert all the songs in a folder or on a disk, hold down the Option key (Mac) or Shift key (Windows) and choose Advanced > ConvertImport preference setting. The Import preference setting will match what you chose in step 3. iTunes will prompt you for the location of the folder or disk you want to import and convert. All the songs in the folder or on the disk will be converted. Note: Some purchased songs are encoded using a protected AAC format that prevents them from being converted. iTunes Plus purchases are not protected and can be converted.

The song in its original format and the newly converted song appear in your library.