To change the alignment of the content, we use the text-align property.

<html>
<head>
<style>
.center{
text-align:center;
border-radius:100px;
background-color: lightBlue ;
}
</style>
</head>
<body>
<h1 class="center">Welcome!</h1>
</body>
</html>]]>

Make sure to pick text-align.