how to center element in html code example

Example 1: center with css

.parent {
  position: relative;
}
.child {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

Example 2: how to center an image element inside a block in css

img { display:block;
      margin-left: auto;
      margin-right:auto;
      }

Example 3: how to center div

<!DOCTYPE html>
<html>
<head>
<style>
.center {
  margin: auto;
  width: 80%;
  border: 3px solid #73AD21;
  padding: 10px; # deals with margins within the element itself
  margin: 20px; # deals with area around outside of element
}
</style>
</head>
<body>

<h2>Center Align Elements</h2>
<p>To horizontally center a block element (like div), use margin: auto;</p>

<div class="center">
  <p><b>Note: </b>Using margin:auto will not work in IE8, unless a !DOCTYPE is declared.</p>
</div>

</body>
</html>