I am learning 9 patch
in Android but when I open I am just getting below image.

Now I am confused on how to start the 9 patch as nothing is present here to start.
You must open an existing file (this is not a DRAWING program).
To create a button image. either:
- use Google/Images/select some you like
- make some in Paint/Gimp/PhotoShop
- or take them from the android SDK
The choice is broad.
The rest of the process is trivial:
- add a 1px border on each side of your picture
- add the black pixels (up and left side to set the stretchable area/s, right and bottom sides to set the padding - mostly used for keeping the text evenly spaced from the boundaries)
- save the file as my_file.9.png (.9.png!)
- drag'n'drop it into the tool to adjust it