CSS Border Radius 

<!DOCTYPE html>
<html>
<head>
  <title>HTML Example with CSS Border Radius</title>
  <style>
    .rounded-element {
      width: 300px;
      height: 300px;
      background-color: #f1f1f1;
      border-radius: 10px;
      text-align: center;
      line-height: 300px;
    }

  </style>
</head>
<body>
  <div class="rounded-element">
    <h1>Rounded Element</h1>
   </div>
   <p>This element has rounded corners<br> 
   created using CSS border-radius property.</p>
</body>
</html>

Code Output

CSS Border Radius

It is a property that allows you to create rounded corners for elements.