Add the comma-separated list of shadows to add more than one shadow, with the text-shadow property. You can try to run the following to learn how to add multiple shadows in a single line
Example
<!DOCTYPE html>
<html>
<head>
<style>
h1 {
text-shadow: 0 0 3px red, 0 0 4px green, 0 0 5px blue;
}
</style>
</head>
<body>
<h1>Heading One</h1>
<p>Above heading has multiple text shadow effects.</p>
</body>
</html>