Can I file petition for them when they are in US?

Significantly more information is needed in order to provide a legal analysis of ways your parents could attain immigration benefits in the U.S. This includes, for example with what type of visas will you parents plan to enter the U.S. - if with visitor's visas, then beware that entering with a B1/B2 visa requires "nonimmigrant intent," i.e. an intention to remain temporarily for the relevant reason and an intention then to depart. Entering the U.S. with a visitor's visa while intending to be sponsored for permanent residency by an adult U.S. citizen child can have very harsh immigration-related consequences. The same analysis does not apply, however, to parents entering the U.S. with an H1B and H4 visa. There really is no substitute for you and your parents to consult with an immigration attorney who, after learning all of the relevant information, could advise about eligibilities, options, and strategies to attain your goals, and who then could offer legal representation in the often complex application process.