I am making a theme. I can insert logo by editing in header file but how it can be dynamiccaly from wordpress dashboard
I think you are trying to do a "Theme Options" section. It's not so simple to do imo and it is very widely procedure so I recommend Codex lecture.
If you are willing to spend a little cash, you can do it by using "Advanced Customs Fields Options". They even include a video tutorial on how to use it.
You can follow this link to learn more: Advanced Custom Fields