how to make a vertical line on html

1<table class="table table-bordered table-dark">
2  <thead>
3    <tr>
4      <th scope="col">#</th>
5      <th scope="col">First</th>
6      <th scope="col">Last</th>
7      <th scope="col">Handle</th>
8    </tr>
9  </thead>
10  <tbody>
11    <tr>
12      <th scope="row">1</th>
13      <td>Mark</td>
14      <td>Otto</td>
15      <td>@mdo</td>
16    </tr>
17    <tr>
18      <th scope="row">2</th>
19      <td>Jacob</td>
20      <td>Thornton</td>
21      <td>@fat</td>
22    </tr>
23    <tr>
24      <th scope="row">3</th>
25      <td colspan="2">Larry the Bird</td>
26      <td>@twitter</td>
27    </tr>
28  </tbody>
29</table>