Using your example, you could…
<h4><?php echo get_the_title( $post_id ); ?></h4>
Or
$h4 = get_the_title();
echo '<h4>' . $h4 . '</h4>';
More on get_the_title().
Or you could use the_title().
the_title( '<h4>', '</h4>' );
Using your example, you could…
<h4><?php echo get_the_title( $post_id ); ?></h4>
Or
$h4 = get_the_title();
echo '<h4>' . $h4 . '</h4>';
More on get_the_title().
Or you could use the_title().
the_title( '<h4>', '</h4>' );