Retrieve post ID from “querying” URL

Try This Code

 $latest = new WP_Query( array (
    'post_type'    =>'your-post-type-name',
    'post_status'  =>'publish',
    'orderby'               => 'rand',
    'posts_per_page'        => 3
    ));

    while ( $latest -> have_posts() ) : $latest -> the_post();
    echo the_ID();
    endwhile;