How to directly take a photo with a pure white background and how to polish it?

Light distribution

The light is bright and uniform.

If a flash is used,

Test more, just choose a white background.

Customize the white balance preset of the camera. When shooting, the camera setting is bright enough, and the shutter, iso and aperture are controlled by yourself.

If the object is dark, it is easy to take a white background. If it is light, it is necessary to avoid overexposure and set the contrast higher.