I want to create a parabola of collectibles

I am new to unity. I am working on a demo game. Where we will have a functionality of increasing game over a period of time. I do created a prefabs in parabolic shape for collectibles. As the game speed increased player cannot collect all the coins so I want to increase the distance of parabola as game progression. Can anyone help me out in better approach or suggestions. So that, I can achieve this functionality.