If you are in the U.S. and your employer files an I-129 petition, your employer is requesting any of the two things from the petition. First, your employer is requesting USCIS to change your immigration status from current status to a new, employment-based status. Second, your employer is requesting USCIS to extend your legal status in the United States. For H1B Visa Process Visit UT Evaluators
For example, F-1 visa student in US upon completing the study program wants to remain in the U.S. and work for a U.S. employer. To do so, the students can get approval for OPT and work under OPT status but what after the OPT validity expires.
Now the U.S. employer must file the I-129 petition to change the foreign national’s status from F-1 to H-1B (or other work visa status) and extend legal status.
If USCIS denies the I-129, employer can file a second I-129 petition on your behalf, and attempt to correct any flaws that USCIS found in the first petition.For more info on H1B Visa visit Icadl2013
Or, if the shortcomings cannot be corrected at this time, it may be possible to extend your F-1 status in order to remain in the U.S. legally (by opting a master’s program or another degree program).