How to Hide WP-Live Chat by 3CX Admin Menus

function plt_hide_wp_live_chat_support_menus() {
	//Hide the "Live Chat" menu.
	remove_menu_page('wplivechat-menu');
	//Hide the "Live Chat → Getting Started" menu.
	remove_submenu_page('wplivechat-menu', 'wplc-getting-started');
}

add_action('admin_menu', 'plt_hide_wp_live_chat_support_menus', 16);

Where do I put this code?