How to create new file extension and associate an application with it in Windows 8.1?

Question

I want to create a new file extension named ".emsof" and associate any text editor with it like notepad++ in windows 8.1

Moreover all of these files should be searched by having filter of "*.emsof" like any other ordinary files.

Please guide me about how to do it?

Thanks.

Answer 1

1. Create an empty file like myfile.emsof .
2. Double-click it
3. Select Notepad++ as default program.