OPT – Optional Practical Training is a particular period of time(generally 12 months), during which nonimmigrant students holding an F-1 visa and having completed at least 9 months of course work, are permitted to work.
Students with a STEM(Science, Technology, Engineering and Mathematics) degree can apply for a 17 month OPT extension.
However, a lawsuit in November 2014 challenged this extension and the court gave the U.S government time upto Feb 12th, 2016 to formulate new rules. This deadline was extended by 3 months.
An F-1 student is permitted to participate in 2 types of OPT:
You will need a recommendation for OPT from your Designated School Official(DSO).
Your DSO will give you a new Form I-20 with the recommendation.
Once you receive this, apply for an EAD (Employment Authorization Document) with USCIS(U.S citizenship and immigration services) within 30 days.
Fill Form I-765 and apply for Work Authorisation.
USCIS will send you a Form I-766.
Once you receive your EAD, you can start work.