The Loop is WordPress to display posts. Using The Loop, WordPress processes each post to be displayed on the current page, and formats it according to how it matches specified criteria within The Loop tags. Any HTML, PHP or other code placed within The Loop will be repeated on each post.
PHP's syntax
<?php
if ( have_posts() ) {
while ( have_posts() ) {
the_post();
// Post Content here
} // end while
} // end if
?>
The Loop is the important part of each wordpress theme – it is the core of each WordPress site.