You necessarily know these sites based on Spleeter which allow you to separate audio tracks from a simple MP3. That is, to have a voice track and a music track. I had also explained how to integrate this Spleeter technology directly into Ableton.
The thing with all of these sites is that they are mostly paid (well, half free). However today, I offer you a really free one that also does a good job.
Its name is Vocali.se and its operation is simple. You upload an MP3 and you get a zip that will contain 2 MP3s. The first with only the voice (acapella) and the second only with the music (instrumental). This will allow you, for example, if you compose music yourself, to make your own remixes or to use certain loops as samples.
In short, something to have fun.