Each H1B Visa petition filed under the H1b visa program with due procedures are issued with a unique case number by the United States Citizenship and Immigration Services in the form of Receipt Notice.
Once you have your case receipt number, Checking case status online is very easy. Check your case status here
Case status can be checked online for various USCIS services: H1B visa petition, or visa transfer and visa extension application can be checked online for the status. Similarly people applying for green card petition(I-130) for family members or through employer under EB category can check the status for application status for I-140, I-485, AOS, Advance parole, EAD, Citizenship.
Alternatively, you may also obtain your case status by calling 1 (800) 375-5283 using a touch-tone phone, and the automated instructions. Please have your receipt number ready. There is no human intervention in this service. All you get is an electronically recorded message stating your date of application filing and the approximate time frame for the approval. These numbers are generally very busy and not recommended.
Certain applications that are moved to National Visa Service Center (NVC) cannot be checked online. Get more information about NVC and check case status with National Visa Center