There are many ways to isolate vocals from a song. The results vary and can rather depend on your source material. For example if you have an instrumental of the same track you can “invert” that against the original. Mathmatically speaking, it’s the original(with vocals) minus the instrumental (without vocals) equals the vocals. And this effects can be done easily on open source (free) software such as Audacity
If that fills you with dread then don’t be put off – there is a much simpler way. Whilst the result won’t be perfect, this method will certainly allow you a rough separation of vocal and instrument without the need for the instrumental track and as easy as clicking a button. The algorhythms (yes deliberate misspelt pun) on vocalremover.org are pretty impressive. They can make the split on most tracks that you choose to upload. However, choose wisely as it will only allow you to split up to 3 tracks a day.
If you’re a budding amateur muso like myself, you will be fascinated to listen to the accompaniment of many tracks without the distraction or noise of the singer.
I love a good instrumental as one of my Spotify playlists demonstrates.