Form I-94W (the Nonimmigrant visa waiver arrival/departure record) is no longer required to be completed when arriving by air or sea to the United States.
A Customs and Border Protection (CBP) officer will stamp the applicant’s travel authorization with their admission/departure date and their class of admission, after the border inspection has been successfully carried out.
Those who need to prove their status as legal visitors to any US institution that might require it, may access the I-94W form information online. Furthermore, the original I-94W form can be requested during the inspection process at the US border. Note that those travelers who have been give it to border Control officers when leaving the States.