Many homeschooling parents are musically talented and teach their own child (and often others as well) voice or instruments. And, many homeschooling parents are not talented in that area and seek (often struggle) to fill the music.
Most simply have their child take lessons in voice, piano, guitar or some other instruments. Lessons can be obtained through homeschool coops, private sources, churches, community choirs, community bands, and many colleges. Some also join children's theatre groups that put on musicals.
If such resources are not available, you can still learn, by using your library. Ours has recordings in classical music, which you can check out, listen to and supplement with books to learn about the composers. There are also several places on line that offer free online lessons via u-tube.
Bartering is also an option. Trade out a service you can offer for lessons, or tutor or teach someone else's child in exchange for them teaching yours music.
We have at one time or another, been involved in almost off of the above. Instruments played in our home include (or have included--some they have quit on to learn a new one) piano, drums, flute, violin, guitar and harmonica.