Simple, clean, white backgrounds are timeless and offer a high contrast option that can be easy to cut out for placement on other light background colours. If consistency is important, white is also the easiest to replicate over time.
To avoid making these headshots look like passport-style photos, it’s best to incorporate the subject’s character and expressions. Photographing the subject at an angle and using shadow to sculpt the face can help to make these photos look more than your standard ID photo.