My boyfriend is applying for an unmarried visa in the United States. What information should I prepare for him in China?

You give him a birth certificate and an account first (what do you mean, I can't remember clearly)

And four long visa photos.

(I remember giving these at first)

I suggest you ask in the forum first.

Our forum is ticking, and the American immigration section has K 1.

Ask there, or join our internal group.

I am the administrator of the group, and the "lady" is me.