Canvas Changing size

Hey, everyone. I apologize if this has been asked before, but I’m having a problem with my canvas. For whatever reason, the standard border for all of my canvases is set to the size for the standard viewing window. Whenever I choose to maximize on play or build the game, everything on my canvas shrinks. Can somebody tell me what’s going on? Thanks a bunch.

The problem is that it doesn’t change the size at all. Is stays the same pixel size so when you make it fulscreen it doesn’t change size in pixels. I am new too so I don’t know how to fix it but you could search up something like how to change the size of gui depending on device screen size.