how to align text horizontal in html code example

Example 1: css align items vertical center

.parent {
  display: flex;
  justify-content: center;
  align-items: center;
}

Example 2: text vertical align css

<!DOCTYPE html>
<html>
  <head>
    <title>Title of the document</title>
    <style type="text/css">
      div {
        display: table-cell;
        width: 250px;
        height: 200px;
        vertical-align: middle;
      }
    </style>
  </head>
  <body>
    <div>Vertically aligned text</div>
  </body>
</html>

Example 3: css align center

.center {
  margin: auto;
  width: 50%;
  border: 3px solid green;
  padding: 10px;
}