Getting the WordPress Post ID of current post

Try using this:

$id = get_the_ID();

In some cases, such as when you're outside The Loop, you may need to use get_queried_object_id() instead of get_the_ID().

$post_id = get_queried_object_id();

global $post;
echo $post->ID;

You can use $post->ID to get the current ID.