wp_query category id code example
Example: category name wp query
$query = new WP_Query( array( 'category_name' => 'staff' ) );
cat (int) – use category id.
category_name (string) – use category slug.
category__and (array) – use category id.
category__in (array) – use category id.
category__not_in (array) – use category id.