Default app (not deep linking)

Is there any extension to make an app default. I didn't find in taifun website. I am not talking about deep linking like when you search in a browser and click on a link the app opens.But, I am talking about default app i.e when we click on a pdf file,it gives options of many apps to open it with and make it the default.
How to get your app also to that list?

The solution to this question about default app is not given