<!DOCTYPE html> <html> <head> <style> table, th, td { border: 1px solid black; border-collapse: collapse; } </style> </head> <body> <h2>Table Headers</h2> <p>Use the TH element to define table headers.</p> <table style="width:100%"> <tr> <th>Firstname</th> <th>Lastname</th> <th>Age</th> </tr> <tr> <td>Jill</td> <td>Smith</td> <td>50</td> </tr> <tr> <td>Eve</td> <td>Jackson</td> <td>94</td> </tr> </table> </body> </html>