Hi,
I am in US on a F2 visa. I don't work in US but overseas in Offshore drilling. During my leave I stay with my family in US. My salary is credited in bank in US and by my office in US.

Do I have to file tax?? If so How?

Thanks

F2 visa holders can not work in the U.S. Unlike F1, your days in the U.S. are not exempt from residency. Once you meet Substantial Presence Test, you must report all your worldwide income on the U.S. tax return.

That is not correct.

Since the money was NOT earned within the confines of the U.S. the U.S. has NO legal standing to tax the income, especially for a non-resident alien under a F-2 visa.