Form I-797 is not a form that can be downloaded online, nor can it be filled out, according to the U.S. Citizenship and Immigration Services, or USCIS. Rather, the USCIS issues it to notify a customer of an immigration benefit for which he applied.
Form I-797, notice of action, is issued by the USCIS pursuant to an immigration-related application or a petition made by a foreign national to change her non-immigration classification, explains the University of New Hampshire Office of International Students & Scholars. The USCIS issues it as confirmation of its application approval.
The USCIS issues several types of Form 1-797, such as, I-797A, which serves as a replacement for an I-94 form; I-797B, which verifies an alien worker petition approval; and I-797C, which communicates receipt of payment, application status, and case re-openings.