You can change the background color of the cell or text color.
By default the background color of the cell is white in MS Excel. You can change it as per your need from Home tab » Font group » Background color.
By default, the foreground or text color is black in MS Excel. You can change it as per your need from Home tab » Font group » Foreground color.
Also you can change the foreground color by selecting the cell Right click » Format cells » Font Tab » Color.