All digital cameras have an auto white balance setting that allows the camera to detect the color of the light and balance it correctly.
When you look at a white object, say the page of a book or a sheet of white paper, it appears white to you regardless of the light source. When lit by an ordinary household bulb, or a florescent light, or outside in daylight it still looks white to your eye.
But to the camera’s eye, each of these light sources is different and each produces a tint of color on the white object. And unless the camera makes some sort of adjustment for this variation in light color, a white object will not appear white in your photos.