To create red neon glow shadow, use the text-shadow property. You can try to run the following code to achieve this
Example
<!DOCTYPE html>
<html>
<head>
<style>
h1 {
text-shadow: 0 0 4px #FF0000;
}
</style>
</head>
<body>
<h1>Heading One</h1>
<p>Above heading has a read neon glow shadow effect.</p>
</body>
</html>