First of all you need to add below code to the function.php of your WordPress theme.
add_shortcode('field', 'shortcode_field');
function shortcode_field($atts){
extract(shortcode_atts(array(
'post_id' => NULL,
), $atts));
if(!isset($atts[0])) return;
$field = esc_attr($atts[0]);
global $post;
$post_id = (NULL === $post_id) ? $post->ID : $post_id;
return get_post_meta($post_id, $field, true);
}
Now use the below Shortcode inside pages or posts to display custom field value.
Make sure the ID of the Shortcode field below should be same as the name of the custom field.
[field “my-block”]