How to put title slug into content when create a new post?

You have to use the_content filter.

Following example is to just adds a featured image set from the single post Edit screen which displays before the content on single posts only.

You can change it to display title and permalink.

add_filter( 'the_content', 'featured_image_before_content' ); 

 function featured_image_before_content( $content ) { 
    if ( is_singular('post') && has_post_thumbnail()) {
        $thumbnail = get_the_post_thumbnail();

        $content = $thumbnail . $content;

        }

    return $content;
}

Source : Plugin API/Filter Reference/the content