How does teeth whitening work?

It's not that the teeth are white, but I have a slight concern.

How does teeth whitening work in terms of its mechanism?

Shall I make it white? Whitening is about turning yellow teeth into white ones.

It probably means making it look nice and white.

Are you grinding it down to make it white?

I'm suddenly curious, so I'm leaving a message. What about teeth whitening toothpaste?

I tried listening and using it, but I didn't see much effect, so I went to the dentist.

I'm suddenly curious about what teeth whitening procedure is.

Please let me know if anyone knows. Thank you. Haha.