How to Hide the "VPN leaks test" Admin Menu

function plt_hide_vpn_leaks_test_menus() {
	//Hide the "Settings → VPN leaks test" menu.
	remove_submenu_page('options-general.php', 'vltp-admin-page');
}

add_action('admin_menu', 'plt_hide_vpn_leaks_test_menus', 11);

Where do I put this code?