How can you make a white background of a TextButton or ImageLabel turn into a clear one?

GUIs like Frames,ImageLabels,TextButtons and more all have one property. The BackgroundTransparency. No scripting really needed. Just change it like how you would change the transparency of a part.

Gui.BackgroundTransparency = 0.5 --Lets say Gui is a variable of a gui.

You can also change the color of it. This is BackgroundColor3. It has Color3 because it is a Color3 Value. Note that Color3 is not (255,255,255) it is actually (1,1,1). So to make it a certain shade of blue or any color(in this case, blue.) we have to make is a decimal number: 0,0,0.18365483. Or just divide a number by 255.

Gui.BackgroundColor3 = Color3.new() --If it's left blank, it will have no color.(Black)
Gui.BackgroundColor3 = Color3.new(1,1,1) --White
Gui.BackgroundColor3 = Color3.new(127/255,127/255,127/255) --A shade of grey/gray.

Hope it helps! Learn more about gui's here.