HTML colors are used to add color to text, background, etc & defined by the name of the predefined color value.
A color name can be RGB, HEX, HSL, RGBA, HSLA color names, or values.
Text Color and background:
<!DOCTYPE html>
<html>
<body>
<h3 style="color:green;background:#0099ff">Rathorji</h3>
</body>
</html>
Border Color
<!DOCTYPE html>
<html>
<body>
<p style="border: 2px solid blue;">Rathorji</p>
</body>
</html>