Display draft posts on single pages [duplicate]

You need to change into the code, by default wordpress shows only post which are published. In your case you need to change the

$args = array(
    'post_status' => array( 'publish', 'draft')
);
$query = new WP_Query( $args );

for more info you can look into this link:

Another thing you can alter your current query using query post like query_posts(&post_status=draft)