i have viewed desktop code of elementary OS and i have some ideas for the desktop can i modify the code and push it directly ? or there is a procedures that i have to do it first ?
If you don't know where to begin, try the developer guide they provide, it helps a lot.
Unfortunately developing an OS don't work this way, you have to start a issue on launchpad or github (depending on the project you are working on), with the reasons why this feature should be implemented. If the team is OK with your feature you can start to code it, then the code reviewed and if it's according to the coding standard, it get implemented.