How to Hide Zoho Mail Admin Menus

function plt_hide_zoho_mail_menus() {
	//Hide "Zoho Mail".
	remove_menu_page('zmail-integ-settings');
	//Hide "Zoho Mail → Configure Account".
	remove_submenu_page('zmail-integ-settings', 'zmail-integ-settings');
	//Hide "Zoho Mail → Test Mail".
	remove_submenu_page('zmail-integ-settings', 'zmail-send-mail');
	//Hide "Zoho Mail → Troubleshoot".
	remove_submenu_page('zmail-integ-settings', 'zmail-troubleshoot');
}

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

Where do I put this code?