How to take photos with black background by photography?

As long as the background is black. Then the light should not be too bright. The most important thing is to choose spot metering as the metering method, and the focusing spot metering points are all above the object. In this way, the already dark colors around are darker because of spot metering.

As for the lighting, you can't use the camera flash directly. In a flash, it turned white. Illuminate an object with a special lamp. The light is softer.