How long does it take to get the US CIS receipt notice (Form I-797 – Notice of Action) after I have mailed my OPT application to US CIS?
You can expect to receive Form I-797 (Notice of Action) from USCIS usually within 2-4 weeks after mailing your OPT application. Be sure to safeguard this form. The Notice of Action is proof that Service Center has received your OPT application and has begun to process it and includes a tracking number so that your application can be identified.