Any time you make something, you have a copyright on it.
I don’t think that is quite true. I think there is a minium bar of human creativity needed for copyright to apply to something. If you accidental knock some paint over onto a bit of paper you do not get copyright over the result. But if you pick some paint, and intentionally throw it at a canvas in deliberate motions you have a much stronger claim of copyright over that work.
The work i believe also needs to be big enough to be able to claim copyright. A single sentence might not be enough, like how you cannot copyright a single cord in music.