Make part fit like the camera

i have a part, and i want it to fill the whole screen of the camera part and not fill anymore, here’s a picture of what it is

Do you mean block the camera’s view or be the exact size of the camera part?

exact size of the screen i suppose

You should look into camera FOV and scaling adaptively. I have never done this before so I am assuming that the screen size could change and mess up how the block covers the screen.