Googlebot script. Where should I put it?

There is a free php script that notifies us when googlebot TM visits our page. To install this script, simply copy paste into your page and edit email address you want to be notified. You can find the script at https://www.smartphpscripts.com/bot-monitor/

My question is, where should I put this code? Inside footer.php or….

Please help, I am newbie in WP

Thanks