I-9 (Different from I-94, see below for I-94 definition and description)
Employment Eligibility Verification
Reference : http://www.uscis.gov/i-9
Application to Register Permanent Residence or Adjust Status
Reference : http://www.uscis.gov/i-485
USCIS uses numerous types of Form I-797 to communicate with customers or convey an immigration benefit. Form I-797 is NOT a form you can fill out. The chart below gives a brief description of each:
|I-797, Notice of Action||Issued when an application or petition is approved.|
|I-797A, Notice of Action||Issued to an applicant as a replacement Form I-94.|
|I-797B, Notice of Action||Issued for approval of an alien worker petition.|
|I-797C, Notice of Action||Issued to communicate receipt of payments, rejection of applications, transfer of files, fingerprint biometric, interview and re-scheduled appointments, and re-open cases.|
|I-797D||Accompanies benefit cards.|
|I-797E, Notice of Action||Issued to request evidence.|
|I-797F, Transportation Letter||Issued overseas to allow applicants to travel.|
Reference : http://www.uscis.gov/i-797-info
I-94 is issued to keep Arrival or Departure record to monitor over stays etc. If one overstays past the date stamped (or stated on the electronic document*) then he/she will have issues at re-entry. Electronic I-94 can be obtained here https://i94.cbp.dhs.gov/.
Also, the link provides a document of travel history of that individual. The form uses Name, Date of Birth and Passport Details to pull up the I-94 records.
The I-94 is the Arrival / Departure Record, in either paper or electronic format, issued by a Customs and Border Protection (CBP) Officer to foreign visitors entering the United States. After April 30, 2013, most Arrival/Departure records will be created electronically upon arrival. Instead of a paper form, the visitor will be provided with an annotated stamp in the foreign passport. If provided a paper form, the admitting CBP Officer generally attaches the I-94 to the visitor’s passport and stamps the departure date on the form.
In both circumstances, an electronic I-94 or paper I-94, the visitor must exit the U.S. on or before that date stamped on the form or in the passport.
If a visitor departs by a commercial air or sea carrier (airlines or cruise ships), their departure from the U.S. can be independently verified and it is not necessary to take any further action, although holding on to the outbound (from the U.S.) boarding pass – if they still have it – can help facilitate reentry when coming back to the United States.
If a visitor departs by land and has a paper form I-94, the I-94 must be turned in to a CBP Officer at a land border when exiting the U.S. If it is not turned in to a CBP Officer at the land border, the visitor will be considered an “overstay” and they may be denied entry when they attempt to reenter the United States in the future.
Reference : https://help.cbp.gov/app/answers/detail/a_id/880/~/definition-of-an-i-94