If you want to stop your site spam comment you need to choose any option. Many options are available online. But thus tools are taken many times to load your site and fell boring. In my mind Google recaptcha is best to use any site and it is easy to use. But in this tutorial I only show in wordpress cms platform.
First Go this link and https://wordpress.org/plugins/wp-recaptcha/ download wordpress plugins. Then Upload it in your wordpress plugins Next just you need to activate this plugins. Or Go to your wordpress Dashboard >> Plugins>> Add New Next Search this plugins using this keyword “WP-reCAPTCHA” then same process to active your plugin.
When your plugins is active you see another option in your wordpress dashboard under Settings. To enable this you need to key one is public key and another is private key. Now you definitely think where you got thus keys. Don’t worried I also tell you where you fine thus keys. Just follow me.
Then go https://www.google.com/recaptcha login here using your Gmail account. You see a form like this. Just put your site label means your site title and your domain name (Just put your domain name without http:// and www)