how to get post category name in wordpress code example

Example 1: wordpress get post category name

<?php
$categories = get_the_category();
 
if ( ! empty( $categories ) ) {
    echo esc_html( $categories[0]->name ); // Show first item of category  
}
?>

Example 2: Get wordpress posts by category name..!

<?php query_posts('category_name=CATEGORYNAME&showposts=5');

while (have_posts()) : the_post(); ?>

the_title();   // To display the title of all posts that have category name selected 

the_content();   // To display the content of all posts that have category name selected 


<?php endwhile; ?>