how do i create a karaoke file from a mp3 file?

Answer 1

With a standard MP3 audio track you would first need to reduce the lead vocals in order to sing over them without them being heard. Then you would need the right software to add the lyrics, synchronized to the music. See the link below for more information.

Answer 2

a few softwares r avilble, nyway they doesnt work well to perform on a stage....