Meta box or shortcode help

First create the meta box with a simple input value to insert the text you want. Here is a good example.

Then you take the input from the meta box and create a function to store it as a shortcode. Check out the Shortcode API to enable the shortcode. Something like this should do the trick:

function new_title( $atts ) {
    if (!isset ($_POST['your_meta_input'])) {
        return;
    }

     else {
        return $_POST['your_meta_input'];
     }
 }

add_shortcode( 'city', 'new_title');