Display Current User Display Name

<?php
function display_current_user_name() {

    if ( ! is_user_logged_in() ) {
        return '<p>Please log in to view your name.</p>';
    }

    $user = wp_get_current_user();

    return '<p><strong>Name:</strong> ' . esc_html( $user->display_name ) . '</p>';
}

add_shortcode( 'current_user_name', 'display_current_user_name' );