In order to obtain U.S. lawful permanent residence (a green card), many people who have spent more than 180 days in the U.S. illegally must apply for a waiver of that unlawful presence in order to avoid a time bar of three or ten years. For those living in the U.S. already, however, applying for the waiver at an overseas consulate, while attending their immigrant visa interview, carries the risk that it will be denied and they will be stuck overseas for the time-barred period. That's why the provisional waiver was created--to allow applications to be made before departing the United States. It's a complicated subject, however. Learn more here.
No premium processing is available for provisional waiver requests, but a few people may successfully request expedited processing, such as for a medical, humanitarian, or similar emergency, or the possibility of severe financial loss to a business or a person.
I Overstayed a Visa and Am Marrying a U.S. Citizen: Do I Need an I-601 Waiver?
Immediate relatives who entered the U.S. legally probably don't need an unlawful presence waiver.
What Are the Chances That My I-601 Waiver Will Be Granted?
USCIS approval of an I-601 waiver application is anything but automatic, particularly when it involves an extreme hardship determination. Find out how to improve your chances of success.