"English" is the adjective. "Englishman" and "Englishwoman" are nouns. "I am English." or "You are English" are correct. "I am an Englishman," or "You are an Englishwoman" are correct. ("an" is an article that goes with a noun) "You are an English" is not correct. This is not true for all countries - for example, "American" can be either an adjective or a noun - so "I am American" (adjective) or "I am an American" (noun) are both correct.

I THINK,we say i am english men or woman

"English" means a language itself, a person using this language or anything related to this language. If you'd like to introduce who you are, then you should say "I am an English". But if it is the personal style you want to describe to your friends so that they can get to know you more, then using "I am English" is also correct to say.