請問兩個孩子（18歲和19歲）都是綠卡持有者，他們的父母其中一個是公民，他們要申請入籍需要各自申請N400嗎？還是可以通過公民母親直接從郵局辦理護照？謝謝
-Was the parent got the US citizenship before the kids turned 18 years old? If yes, the kids do not need to file N-400, but file N-600 or directly apply for the US passport to claim their US citizenship. Otherwise, the kids need to file N-400, respectively.
