Unity 2D autoScale the sprite objects in worldspace according to resolution?

Hi all, I'm new to Unity and I'm blocked somewhere. I had gone through almost all questions here and still locked here. Guys please help me.

In my game there are few sprites on world screen and canvas. The canvas are scaling and placing objects perfectly according to screen size. I think that is because of canvas renderer and scalar. But the sprite objects in world space are at constant size. What i need to do for auto scale and place sprite objects in world space.?! when i run on another android device or changing the game window size the object in the world are at same size. Help me