How to Hide the "Hearty Glyph Light" Admin Menu

function plt_hide_hearty_glyph_light_menus() {
	//Hide the "Settings → Hearty Glyph Light" menu.
	remove_submenu_page('options-general.php', 'heartyglyphlight-setting-admin');
}

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

Where do I put this code?