SHOULD WE USE "AN" ONLY BEFORE VOWELS ? .

Yes! But it's not only vowel. It's only vowel sound where we should only use article "an". For ex:- The word "honest" doesn't have the starting letter a vowel, it's "h" and it's a consonant but we use article "an" for it because it has a vowel sound. * An honest (ऑनेस्ट) man

OK . THANKS.

Yes... as well as those word who starts with vowels sound. like An MLA an Honour