I am on H1b visa and my wife is on F1 visa working on OPT. As she is on OPT she was exempted from paying social security & medicare taxes. So if we file tax return jointly as resident, do we need to pay those taxes back? Please suggest
The requirement for paying Social Security and Medicare taxes is based on if she meets the tests to be a Resident on her own. Elections to treat her as a Resident (such as the one required to file Jointly) do not make her an actual Resident yet, so she is not subject to Social Security and Medicare taxes.
Also, What should be the enrollment status for my wife who moved from F1 to F-1 OPT in April 2017. a) A full time student; b) half time student; or c) Less than half-time student?
For what purpose are you asking about being a student? The college makes the determination for what is called "full-time", but for tax purposes, the student usually must be a student for parts of at least 5 months to be called a full-time student. If your wife was only in school for parts of 4 months, she probably would not qualify as a student.