The receipt number is a unique 13-character identifier that USCIS provides for each application or petition it receives. The agency uses it to identify and track its cases.
The receipt number consists of three letters-for example, EAC, WAC, LIN, SRC, NBC, MSC or IOE-and 10 numbers. You can find it on notices of action USCIS has sent you.
Omit dashes ("-") when entering a receipt number. However, you can include all other characters, including asterisks ("*"), if they are listed on your notice as part of the receipt number
Disclaimer : This sample is provided for your convenience and reference purpose only. 
