You can use HTML tags in echo statement of PHP. Here are some of the examples.

1)

<?php
echo "<center>Hello World</center>";
?>

This displays Hello World in center of browser page.

2)This Displays Hello World As H1 tag.

<?php
echo "<h1>Hello World</h1>";
?>

3)This Displays Hello World in red color and font size to 10.

<?php
echo "<h1><font size=10 color=RED> Hello World</font></h1>";
?>

See More Examples