Million vs millions
 

two million people.
two millions of people.
Are they correct?

It isn't proper to add an 's' when a specific number is being said.
We can say 'millions of people', but when a specific number is said, we switch to 'two million people' (notice we don't say 'of').

To properly reference a subgroup, we insert 'of', e.g. 'two million of the people' (it's understood that there are more than two million people, we're only talking about two million of them).

great thanks