How to get current page title inside a page itself in a shortcode and in page content

When i add the

<?php the_title(); ?> 

to a page template file it works and is able to pull the page title inside html tags however if i wanted to add

<?php the_title(); ?> 

to a single page itself how would i do so?

Also to provide more context; i want to add the

<?php the_title(); ?> 

inside a shortcode in order to have the shortcode replace part of it with the specific page’s title, how would i do that?

function post_title_shortcode(){
    return get_the_title();
}
add_shortcode('post_title','post_title_shortcode');