I want to know what kind of Tax liability I will have in USA considering the fact that I will be doing all the services from India, All my expenses will also incur in India.=========No US tax liability for your biz UNLESS you were physically present in US or your biz is done in US. Income that is effectively connected with a U.S. trade / business is taxable to US is often connected with the fact that the foreign corporation has a fixed base or permanent establishment in the U.S. i.e. it has some sort of permanent office, factory, base of operations, etc., in the U.S. from which it generates its U.S. income.
However, if you set up your biz in US, then you need to pay some amount of franchise fee to the state; to do business in the U.S., a foreign corporation must be registered at the federal level of a country or at the state or province level of US.
In case I have the tax liability, please let me know on what I need to pay the tax ? for example for a service for which I will receive $100 , I have expenses of $65 ( this involve employee salary , setup expenses, rent, local indian taxes etc) , So I will be liable for taxes in usa for remaining 35$ or entire 100$Please suggest :Also please note that I am currently not in USA.==>As mentioned above you are NOT liable for biz taxes to US.