Change the WordPress title field placeholder text

Really handy snippet to change the "Enter title here" text to suit your post type better.

Just paste this to your functions.php, change the POST_TYPE and the default text.

function change_default_title( $title ){
     $screen = get_current_screen();
     if  ( 'POST_TYPE' == $screen->post_type ) {
          $title = 'Enter Invoice Title';
     }
     return $title;
}
add_filter( 'enter_title_here', 'change_default_title' );

Source