How to save all scene?

Im trying to save everything while its playing and when you give click on a button called save it save all, but the problem its that I don't Know how to save everything, gameobjects, prefabs, any changes you make, in few words SAVE ALL SCENE. So when you save it and you close unity and then you open it and you play it, it will be all exactly how it was.

If someone know please tell me. :)