I am an American green card now. I didn't write about my daughter when I applied. Can I apply for immigration for my daughter again? What should I do?

"I didn't write about my daughter when I applied" means that you didn't mention that you have this daughter in your application materials at all; Or is there information about your daughter in the application materials, but you didn't apply for her to immigrate together? If it is the latter, you can wait in line for the result by submitting the application to the immigration office and paying the application fee. If it is the former, it will be more troublesome, and the immigration officer will think that you were dishonest at the beginning; I suggest you consult an experienced consulting company.