I am on H1B visa. I want to file for tax extension for Married filling jointly.  My wife does not have both SSN and ITIN .She is currently in India and she will not be back till May 2.  As I understand, if I am expecting refund neither me nor my wife need to EXPLICITLY request for extension, It is implied that I can file for 2015 tax returns even after the 4/18 due date and I can apply for my wife's ITIN while filing my tax return when she comes back. So as of now I do not have any action item and just wait until my wife comes back to file tax return. Please confirm.