<!DOCTYPE html>
<html>
<head>
<style>
table, th, td {
border: 1px solid black;
}
</style>
</head>
<body>
<h1>Table Headers</h1>
<h2>Horizontal headers:</h2>
<table>
<tr>
<th>Name</th>
<th>Email</th>
<th>Phone</th>
</tr>
<tr>
<td>John Doe</td>
<td>john.doe@example.com</td>
<td>123-45-678</td>
</tr>
</table>
<h2>Vertical headers:</h2>
<table>
<tr>
<th>Name:</th>
<td>John Doe</td>
</tr>
<tr>
<th>Email:</th>
<td>john.doe@example.com</td>
</tr>
<tr>
<th>Phone:</th>
<td>123-45-678</td>
</tr>
</table>
</body>
</html>