I downloaded the latest version of audacity for the first time. I do not have the mono option in the dropdown menu, so I can’t do the basic function to take out lead vocals. Please advise.

You can use the Vocal Removal Effect and you don’t have to make mono. That will give you a “stereo” file with identical sound in both channels.

There is a little drop-down arrow to the left of the waveform. Click that and you’ll see Split Stereo To Mono. That will give you two mono tracks and when you export they will be mixed to a single-mono track.

Thank you. But how do I keep the background vocals?

But how do I keep the background vocals?

Vocal Removal removes anything in left-right dead center of a stereo show. It doesn’t actually “know” what a voice is. In the classic Vocal Removal, the drums and bass can vanish too. They normally mix to the middle. If the background singers are in the middle, they’re going to vanish, too.

In this example, the lead was mixed with stereo echo which stayed around. Note the bass went away.

There’s a long list of problems that can cause vocal removal to fail. It doesn’t work at all on a mono or two-track mono show.

Audacity can’t split apart a song into individual voices, instruments and sounds. If this didn’t do it for you, start Googling for your song mixed with no lead singer—a karaoke mix.