Depends on where you want the color.
E.g., you can change the background of the entire page on the <BODY> tag:
<BODY bgcolor="#727272"> <!-- dark grey -->
You can change the color of your text in the <FONT> tag:
<FONT color="#EE0000">This text should be red</FONT>
Or you can make similar changes in CSS styles.
(Like it or not, I don't think it works with the British spelling, "colour")