Please help me out how to convert a inDesign file into MS word application.
The best way is to rebuild it in Word from scratch as there is pretty much no way to covert between the two formats properly or in an automatic sense.
There’s probably sites online that would tell you to export it as a PDF and they try saving that out for Word but in reality this will not work properly.
The files on envato are also quite advanced making unintended conversion even harder, but there are some items which include a MS Word version so your best option is to search through and find one of those.