Searching the contents of InDesign files is not a built-in Windows function. Windows Search can only find text in basic, plain text files.
Alternative: Markzware's PageZephyr (InDesign CS6 Content Search, How to Search InDesign Files: PageZephyr)
I have a file locator program which searches for english text but failing to search indic language text
So that is not the Windows built-in search then.
There are several reasons why a general utility fails. Text in InDesign files cannot be searched with a simple general text finder. They are binary files, and text is stored in discontinous chunks. That is why it needs a special application. Furthermore, "English" - I presume you mean basic ASCII - text is not encoded, but everything beyond it is, in multibyte Unicode sequences. You can only search Unicode text if you know the storage format of InDesign files, and/or your search utility uses the same convention.
You mean we can only select the unicode text, even i am also asking for same thing, i am asking for devnagri unicode text