I think we need to clarify a couple of definitions:
Native English speaker – A person whose first language is English (they learned English from birth or as a very young child), and for whom English is the primary means of communication.
Fluent English speaker – A person who learned English later in life (i.e. as an older child, teenager, or adult), and who is very proficient in both spoken and written English.
There is nothing wrong with not being a native English speaker, and many non-native speakers have far better English skills than myriads of native speakers.
Do the needful is Indian English, which has been covered on ELU.
If you're only interacting with other speakers of Indian English then feel free to use it, but avoid it in any other contexts (most Americans and Brits will think it's quaint/uneducated).
In general, the "standard" form is do what[ever] is necessary, but in OP's specific context most likely nothing like that would be used anyway. If you've just asked for an email address, it goes without saying that you want the other person to do whatever is necessary to give you that information.
I may be wrong, but I have the impression that for many Indian English speakers, "Please do the needful" carries a subtext of "This problem is too complex for me to understand or resolve myself, but I have complete faith that you will be able to deal with it, because you are very skilled in such matters"
As I said, Brits and Americans wouldn't normally use any equivalent for such a trivial problem as finding someone's email address. But if the request was for something more challenging (and crucially, if it was from a manager to a more junior worker), "Do what[ever] [you think] is necessary [to solve this problem]" might be perfectly normal. The implication there is that the manager is authorising the junior to do things he might otherwise not be "permitted" to do (in effect, the junior is being temporarily "promoted" for the duration of the problem-solving).
In that context, it should be clear that (to Americans or Brits, at least) any such phrase would probably be considered offensive/cheeky if addressed to an equal in the workplace (if the person asking isn't senior enough to confer temporary authority on you, they shouldn't be speaking to you that way).
Best Answer
While “get something made” is an acceptable form in some sentence constructions, it is not idiomatic (in ordinary English) in the instances shown in the question. In the US, those questions would be phrased as in some of the following examples.