English question, please help?

Both instances are correct, and both are used by native speakers, at least in British English. It is important to use the correct word and sentence stress, however, such that:

(1) May i /ask/ where you are /from/? (equal sentence stress falls on 'ask' and 'from')
(2) May i ask, WHERE are you /from/? ('where' and 'from' are stressed, with predominant sentence stress on 'where').

Note also, the comma, which is mandatory in sentence type (2). If you omit the comma, you must invert the verb, which results in sentence type (1).

The same applies to your other examples.

yes sometimes in oral english first is right , sometimes ,in formal english second is right

ummm i would say that may i ask where you are from is correct
and may i ask who you are ...are correct.
scratch the other 2.

May I know where you are from ?
May I know who you are ?
always remember,if you use a sentence after a verb,that sentence should always be a statement.of course,there are several exceptions.