急请863211老师，PIJIANG老师 for I-94

I took my niece to register for comunity college course, the lady checked her password and asked about  I-94, that's why I knew she didn't have it stapled on her password. my sister and her daughter filled I-94, gave to officer when they arrived airport. Since they come with  immigration visa (F-4), and still wait for real green cardp to be mail to them. Does they  need I-94 ? How can they request again ?

Thanks