If I visit US and register my company there, can my visa for me and my children be changed from b2 visa to L1 visa?

Significantly more information is needed in order to provide a legal analysis of whether a change of status to L1 is a viable strategy. That includes, for example, information about your Indian company, information about your length of employment, information about your skills, etc. There really is no substitute for you 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.