The Green Card is an extremely important document because it allows foreigners to live and work legally in U.S. territory. If it got lost, it is essential to report it immediately, and request a duplicate. Otherwise, you are at risk of having your residence canceled.
How to Request a Duplicate of the Green Card
First, you have to fill in a form called I-90 at USCIS (Office of Immigration and Citizenship). You should complete this form with a black pen and in capital letters.
It is also important that the I-90 form is signed by the owner of the Green Card. If he or she is under 14 years old, it must also be signed by one of his or her parents.
How Much Does a Duplicate Cost? 
A Green Card duplicate costs about $450. Of these, $365 are for the application, and the remaining $85 are for biometrics.
Validity
A Green Card is usually valid for 10 years. It must be renewed six months before its expiration date.