how to put new color at button when mouse are in the button?

so all what i want is to when i put my mouse on the textbutton i get new color and when i left it go to normal

There are some events you should know about called MouseEnter and MouseLeave for TextButtons, ImageLabels etc that you can use to achieve this effect. Something like this:

function entered()
	gui.Color = Color3.new(color you want)
end

function left()
	gui.Color = Color3.new(color you want)
end

gui.MouseEnter:connect(entered)
gui.MouseEnter:connect(left)