get post by category id 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: wordpress get post by id

$post   = get_post( 123 ); // Where 123 is the ID
$output =  apply_filters( 'the_content', $post->post_content );