<br> is used to drop down one line break, and <hr> is used for the horizontal line that splits sections.
Watch out — stacking a bunch of <br><br><br> just to get paragraph spacing isn't professional. It's better to handle layout spacing with CSS margin/padding.
html
<p>This is the first line.<br>This is the second line.</p>
<hr>
<p>This is another section.</p>You should see
You'll see a line break, a divider line, then the next paragraph.