You can enter a song’s lyrics into iTunes and view them at any time.
You can’t add lyrics to some types of files, such as WAV and QuickTime files.
Select a song and choose File > Get Info.
Click Lyrics.
Enter the words to the song, or view lyrics you’ve entered previously.
With some iOS devices and iPod models, you can view a song’s lyrics on the device if you’ve entered them in iTunes. See the documentation that came with your device for more information.