Do I ( H1b) have to file any thing for my wife ( H4)while my employer files a i140 application for me.

Hello, I would really appreciate your thoughts? I am currently on H1b visa and my wife on H4. I am a physical therapist from India. My employer just completed filing perm labor and now is going to apply for i-140 application. The lawyer who he has hired said that she will have to file an application for my wife while she files a i-140 for me? She said that it would be at extra cost and a filing fee for her too? May i know what kind of form is she talking about? Can you put some light to this topic which could make things clear to me?